Failed to decode packet `clientbound/minecraft:custom_payload`

Summary

Client disconnected with reason: Internal Exception: io.netty.handler.codec.DecoderException: Failed to decode packet clientbound/minecraft:custom_payload

Steps to reproduce

Reproducing it is quite challenging and inconsistent.

Join a Cobblemon server

Sometimes, it takes a few tries to get it to crash.

Join a Cobblemon server
Restart the client
Re-join the same Cobblemon server

What is the current bug behavior?

A crash screen appears.

What is the expected correct behavior?

The server should be joined.

Sometimes, joining twice in a row works, but sometimes, it doesn't work even with repeated logins.

Sometimes, restarting the server makes it work.

Cobblemon Version and Mod Loader

Cobblemon 1.7.2
Fabric Loader 0.18.4

Mods used besides Cobblemon

Client-side

Accessories [1.1.0-beta.52+1.21.1]
AmbientSounds [6.3.3]
Architectury [13.0.8]
Auto Clicker [21.1.1]
Balm [21.0.56]
CIT Resewn [1.2.2+1.21]
Capes [1.5.4+1.21]
Cloth Config v15 [15.0.140]
CobbleDollars [2.0.0+Beta-5.1+1.21.1]
Cobblemon [1.7.2+1.21.1]
Cobblemon Additions [4.2.1]
Cobblemon Capture XP [1.7.2-fabric-1.3.0]
Cobblemon Effectiveness [0.3]
Cobblemon Extra Structures [1.2.0]
Cobblemon Knowlogy [1.5.0]
Cobblemon:Mega Showdown [1.6.2+1.7.2+1.21.1]
CobblemonExtras [1.5.0]
Cobbreeding [2.1.1]
CreativeCore [2.13.24]
Distant Horizons [2.4.5-b]
Dynamic FPS [3.11.3]
Entity Model Features [3.0.10]
Entity Texture Features [7.0.8]
Fabric API [0.116.8+1.21.1]
Fabric Language Kotlin [1.13.8+kotlin.2.3.0]
Freecam [1.3.0+mc1.21]
Indium [1.0.35+mc1.21]
Inventory Profiles Next [2.2.3]
Iris [1.8.8+mc1.21.1]
Knowlogy Book [0.9.1]
Krypton [0.2.8]
LambDynamicLights [4.8.7+1.21.1]
Lavender [0.1.15+1.21]
Lithium [0.15.1+mc1.21.1]
MaLiLib [0.21.10]
Mega Showdown Item Pack [1.4.2]
MiniHUD [0.32.60]
Mod Menu [11.0.3]
No Chat Reports [1.21.1-v2.9.1]
Ok Zoomer [10.0.0-beta.11]
Patchouli [1.21.1-92-FABRIC]
PlayerXP [1.0.4+1.21.1]
Rad Gyms [0.3.1-stable]
Radical Cobblemon Trainers API [0.14.6-beta]
Safe Pastures [1.1.1+1.21.1]
SimpleTMs [2.3.3]
Sit [1.21-28]
Sodium [0.6.13+mc1.21.1]
Spawn Notification [1.7.2-fabric-2.3.0]
Switcheroo [1.0.14]
Tim Core [1.7.2-fabric-1.30.0]
VinURL [2.2.1]
Waystones [21.1.25]
XPlus Autofish [1.3.4-fabric-mc1.21.1]
Xaero's Maps x Waystones [2.3.4+1.21.1-fabric]
Xaero's Minimap [25.3.5]
Xaero's World Map [1.40.6]
YetAnotherConfigLib [3.8.2+1.21.1-fabric]
kennytv's epic force close loading screen mod for Fabric [2.2.3]
libIPN [6.6.2]
oωo [0.12.15.4+1.21]

Server-size

accessories-fabric-1.1.0-beta.52+1.21.1.jar
architectury-13.0.8-fabric.jar
balm-fabric-1.21.1-21.0.56.jar
capturexp-fabric-1.7.2-1.3.0.jar
cloth-config-15.0.140-fabric.jar
CobbleDollars-fabric-2.0.0+Beta-5.1+1.21.1.jar
cobblemon-additions-4.2.1.jar
CobblemonExtras-fabric-1.5.0.jar
cobblemonextrastructures-1.21.1-1.2.0-fabric.jar
Cobblemon-fabric-1.7.2+1.21.1.jar
cobblemon_knowlogy-fabric-1.5.0-1.21.1.jar
Cobbreeding-fabric-2.1.1.jar
DistantHorizons-2.4.5-b-1.21.1-fabric-neoforge.jar
fabric-api-0.116.8+1.21.1.jar
fabric-language-kotlin-1.13.8+kotlin.2.3.0.jar
knowlogy-fabric-0.9.1-1.21.1.jar
krypton-0.2.8.jar
lavender-0.1.15+1.21.jar
lightsout-0.0.1+1.20.1.jar
lithium-fabric-0.15.1+mc1.21.1.jar
mega_showdown-fabric-1.6.2+1.7.2+1.21.1.jar
mega-showdown-item-pack-1.4.2.jar
NoChatReports-FABRIC-1.21.1-v2.9.1.jar
owo-lib-0.12.15.4+1.21.jar
Patchouli-1.21.1-92-FABRIC.jar
Pl3xMap-1.21.1-508.jar
playerxp-fabric-1.0.4+1.21.1.jar
Rad Gyms [Cobblemon]-0.3.1-stable.jar
rctapi-fabric-1.21.1-0.14.6-beta.jar
SafePastures-1.1.1+1.21.1.jar
SimpleTMs-fabric-2.3.3.jar
sit-1.21-28.jar
spawnnotification-fabric-1.7.2-2.3.0.jar
timcore-fabric-1.7.2-1.30.0.jar
vinurl-2.2.1+mc1.21.1.jar
waystones-fabric-1.21.1-21.1.25.jar
xaerominimap-fabric-1.21.1-25.3.5.jar
xaeroworldmap-fabric-1.21.1-1.40.6.jar
xmxw-2.3.4+1.21.1-fabric.jar
yet_another_config_lib_v3-3.8.2+1.21.1-fabric.jar

Relevant logs, screenshots and/or videos

https://mclo.gs/RYlHpDr

disconnect-2026-01-26_19.12.20-client.txt

---- Minecraft Network Protocol Error Report ----
// Don't worry, I'll be fine

Time: 2026-01-26 19:12:20
Description: Packet handling error

io.netty.handler.codec.DecoderException: Failed to decode packet 'clientbound/minecraft:custom_payload'
	at knot//net.minecraft.class_9136.method_56425(class_9136.java:38)
	at knot//net.minecraft.class_9136.decode(class_9136.java:14)
	at knot//net.minecraft.class_2543.decode(class_2543.java:31)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:529)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:468)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:290)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.handler.flow.FlowControlHandler.dequeue(FlowControlHandler.java:202)
	at knot//io.netty.handler.flow.FlowControlHandler.channelRead(FlowControlHandler.java:164)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:442)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:346)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:333)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:454)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:290)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:442)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:440)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
	at knot//io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:800)
	at knot//io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:509)
	at knot//io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:407)
	at knot//io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
	at knot//io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Failed to deserialize {"items":"#c:tools/brushes"}: DataResult.Error['Not a json array: "#c:tools/brushes"': (class_2073[items=Optional.empty, count=class_2100[min=Optional.empty, max=Optional.empty, minSq=Optional.empty, maxSq=Optional.empty], components=[], subPredicates={}], {"items":"#c:tools/brushes"})]
	at knot//com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:397)
	at knot//com.google.gson.Gson.fromJson(Gson.java:1227)
	at knot//com.google.gson.Gson.fromJson(Gson.java:1329)
	at knot//com.google.gson.Gson.fromJson(Gson.java:1300)
	at knot//com.google.gson.internal.bind.TreeTypeAdapter$GsonContextImpl.deserialize(TreeTypeAdapter.java:179)
	at knot//com.cobblemon.mod.common.pokemon.adapters.CobblemonRequirementAdapter.deserialize(CobblemonRequirementAdapter.java:93)
	at knot//com.cobblemon.mod.common.pokemon.adapters.CobblemonRequirementAdapter.deserialize(CobblemonRequirementAdapter.java:36)
	at knot//com.google.gson.internal.bind.TreeTypeAdapter.read(TreeTypeAdapter.java:76)
	at knot//com.google.gson.Gson.fromJson(Gson.java:1227)
	at knot//com.google.gson.Gson.fromJson(Gson.java:1137)
	at knot//com.google.gson.Gson.fromJson(Gson.java:1047)
	at knot//com.google.gson.Gson.fromJson(Gson.java:982)
	at knot//com.cobblemon.mod.common.pokemon.adapters.CobblemonRequirementAdapter.decode(CobblemonRequirementAdapter.java:108)
	at knot//com.cobblemon.mod.common.api.interaction.PokemonInteraction$Companion.decode$lambda$0(PokemonInteraction.java:79)
	at knot//com.cobblemon.mod.common.api.interaction.PokemonInteraction$Companion.decode$lambda$1(PokemonInteraction.java:78)
	at knot//net.minecraft.class_2540.method_34068(class_2540.java:150)
	at knot//net.minecraft.class_2540.method_34066(class_2540.java:163)
	at knot//com.cobblemon.mod.common.api.interaction.PokemonInteraction$Companion.decode(PokemonInteraction.java:78)
	at knot//com.cobblemon.mod.common.api.interaction.PokemonInteractionSet$Companion.decode$lambda$2(PokemonInteractionSet.java:50)
	at knot//com.cobblemon.mod.common.api.interaction.PokemonInteractionSet$Companion.decode$lambda$3(PokemonInteractionSet.java:49)
	at knot//net.minecraft.class_2540.method_34068(class_2540.java:150)
	at knot//net.minecraft.class_2540.method_34066(class_2540.java:163)
	at knot//com.cobblemon.mod.common.api.interaction.PokemonInteractionSet$Companion.decode(PokemonInteractionSet.java:49)
	at knot//com.cobblemon.mod.common.net.messages.client.data.PokemonInteractionsSyncPacket$Companion.decode$lambda$0(PokemonInteractionsSyncPacket.java:36)
	at knot//com.cobblemon.mod.common.net.messages.client.data.PokemonInteractionsSyncPacket$Companion.decode$lambda$1(PokemonInteractionsSyncPacket.java:35)
	at knot//net.minecraft.class_2540.method_34068(class_2540.java:150)
	at knot//net.minecraft.class_2540.method_34066(class_2540.java:163)
	at knot//com.cobblemon.mod.common.net.messages.client.data.PokemonInteractionsSyncPacket$Companion.decode(PokemonInteractionsSyncPacket.java:35)
	at knot//com.cobblemon.mod.common.CobblemonNetwork$generateS2CPacketInfoList$96.invoke(CobblemonNetwork.java:335)
	at knot//com.cobblemon.mod.common.CobblemonNetwork$generateS2CPacketInfoList$96.invoke(CobblemonNetwork.java:335)
	at knot//com.cobblemon.mod.common.net.PacketRegisterInfo.codec$lambda$1(PacketRegisterInfo.java:33)
	at knot//net.minecraft.class_9139$1.decode(class_9139.java:20)
	at knot//net.minecraft.class_8710$1.method_56488(class_8710.java:63)
	at knot//net.minecraft.class_8710$1.decode(class_8710.java:39)
	at knot//net.minecraft.class_9139$8.decode(class_9139.java:76)
	at knot//net.minecraft.class_9139$9.method_56441(class_9139.java:91)
	at knot//net.minecraft.class_9139$9.decode(class_9139.java:87)
	at knot//net.minecraft.class_9136.method_56425(class_9136.java:36)
	... 42 more
Caused by: java.lang.IllegalStateException: Failed to deserialize {"items":"#c:tools/brushes"}: DataResult.Error['Not a json array: "#c:tools/brushes"': (class_2073[items=Optional.empty, count=class_2100[min=Optional.empty, max=Optional.empty, minSq=Optional.empty, maxSq=Optional.empty], components=[], subPredicates={}], {"items":"#c:tools/brushes"})]
	at knot//com.cobblemon.mod.common.util.adapters.CodecBackedAdapter.deserialize$lambda$0(CodecBackedAdapter.java:25)
	at java.base/java.util.Optional.orElseThrow(Optional.java:403)
	at knot//com.cobblemon.mod.common.util.adapters.CodecBackedAdapter.deserialize(CodecBackedAdapter.java:24)
	at knot//com.cobblemon.mod.common.pokemon.evolution.adapters.LegacyItemConditionWrapperAdapter.deserialize(LegacyItemConditionWrapperAdapter.java:52)
	at knot//com.cobblemon.mod.common.pokemon.evolution.adapters.LegacyItemConditionWrapperAdapter.deserialize(LegacyItemConditionWrapperAdapter.java:29)
	at knot//com.google.gson.internal.bind.TreeTypeAdapter.read(TreeTypeAdapter.java:76)
	at knot//com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.readIntoField(ReflectiveTypeAdapterFactory.java:212)
	at knot//com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$FieldReflectionAdapter.readField(ReflectiveTypeAdapterFactory.java:433)
	at knot//com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:393)
	... 79 more


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Netty Epoll Client IO #0
Stacktrace:
	at knot//net.minecraft.class_2547.method_55622(class_2547.java:33)

-- Connection --
Details:
	Protocol: play
	Flow: CLIENTBOUND
	Server type: OTHER
	Server brand: fabric
Stacktrace:
	at knot//net.minecraft.class_2547.method_55622(class_2547.java:33)
	at knot//net.minecraft.class_2600.method_59803(class_2600.java:62)
	at knot//net.minecraft.class_8673.method_60882(class_8673.java:136)
	at knot//net.minecraft.class_8673.method_60881(class_8673.java:127)
	at knot//net.minecraft.class_2535.exceptionCaught(class_2535.java:161)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeExceptionCaught(AbstractChannelHandlerContext.java:346)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeExceptionCaught(AbstractChannelHandlerContext.java:325)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireExceptionCaught(AbstractChannelHandlerContext.java:317)
	at knot//io.netty.channel.ChannelInboundHandlerAdapter.exceptionCaught(ChannelInboundHandlerAdapter.java:143)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeExceptionCaught(AbstractChannelHandlerContext.java:346)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:447)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.handler.flow.FlowControlHandler.dequeue(FlowControlHandler.java:202)
	at knot//io.netty.handler.flow.FlowControlHandler.channelRead(FlowControlHandler.java:164)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:442)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:346)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:333)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:454)
	at knot//io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:290)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:442)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at knot//io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:440)
	at knot//io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at knot//io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
	at knot//io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:800)
	at knot//io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:509)
	at knot//io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:407)
	at knot//io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
	at knot//io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at java.base/java.lang.Thread.run(Thread.java:1583)

-- Dynamic Lighting --
Details:
	Description: This section contains information related to dynamic lighting, this may not be related to your crash.
	Mode: fastest
	Dynamic Light Sources: 0
	Spatial Hash Occupancy: 0 / 1024

-- Cobblemon --
Details:
	Version: 1.7.2
	Is Snapshot: false
	Git Commit: b597b14 (https://gitlab.com/cable-mc/cobblemon/-/commit/b597b149c3a227caadd4265408ab2de62e0d0e78)
	Branch: HEAD

-- System Details --
Details:
	Minecraft Version: 1.21.1
	Minecraft Version ID: 1.21.1
	Operating System: Linux (amd64) version 6.17.9-76061709-generic
	Java Version: 21.0.3, Microsoft
	Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Microsoft
	Memory: 2352419840 bytes (2243 MiB) / 4731174912 bytes (4512 MiB) up to 10737418240 bytes (10240 MiB)
	CPUs: 12
	Processor Vendor: AuthenticAMD
	Processor Name: AMD Ryzen 5 5600X 6-Core Processor
	Identifier: AuthenticAMD Family 25 Model 33 Stepping 2
	Microarchitecture: Zen 3
	Frequency (GHz): -0.00
	Number of physical packages: 1
	Number of physical CPUs: 6
	Number of logical CPUs: 12
	Graphics card #0 name: Navi 22 [Radeon RX 6700/6700 XT/6750 XT / 6800M/6850M XT]
	Graphics card #0 vendor: Advanced Micro Devices, Inc. [AMD/ATI] (0x1002)
	Graphics card #0 VRAM (MiB): 16640.00
	Graphics card #0 deviceId: 0x73df
	Graphics card #0 versionInfo: unknown
	Virtual memory max (MiB): 49519.27
	Virtual memory used (MiB): 23018.92
	Swap memory total (MiB): 17406.49
	Swap memory used (MiB): 0.00
	Space in storage for jna.tmpdir (MiB): <path not set>
	Space in storage for org.lwjgl.system.SharedLibraryExtractPath (MiB): <path not set>
	Space in storage for io.netty.native.workdir (MiB): <path not set>
	Space in storage for java.io.tmpdir (MiB): available: 6414.53, total: 6422.55
	Space in storage for workdir (MiB): available: 3154548.00, total: 4758053.00
	JVM Flags: 8 total; -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M -Xms1024m -Xmx10240m
	Fabric Mods:
		accessories: Accessories 1.1.0-beta.52+1.21.1
		ambientsounds: AmbientSounds 6.3.3
		architectury: Architectury 13.0.8
		autoclicker: Auto Clicker 21.1.1
		autofish: XPlus Autofish 1.3.4-fabric-mc1.21.1
		balm: Balm 21.0.56
			kuma_api: KumaAPI 21.0.7
		capes: Capes 1.5.4+1.21
		capture_xp: Cobblemon Capture XP 1.7.2-fabric-1.3.0
		citresewn: CIT Resewn 1.2.2+1.21
			citresewn-defaults: CIT Resewn: Defaults 1.2.2+1.21
		cloth-config: Cloth Config v15 15.0.140
			cloth-basic-math: cloth-basic-math 0.6.1
		cobbledollars: CobbleDollars 2.0.0+Beta-5.1+1.21.1
		cobblemon: Cobblemon 1.7.2+1.21.1
		cobblemon-additions: Cobblemon Additions 4.2.1
		cobblemon_knowlogy: Cobblemon Knowlogy 1.5.0
		cobblemonextrastructures: Cobblemon Extra Structures 1.2.0
		cobbreeding: Cobbreeding 2.1.1
		cobeffectiveness: Cobblemon Effectiveness 0.3
		creativecore: CreativeCore 2.13.24
			net_neoforged_bus: bus 7.2.0
		distanthorizons: Distant Horizons 2.4.5-b
			fabric-api-base: Fabric API Base 0.4.42+6573ed8c19
			fabric-command-api-v2: Fabric Command API (v2) 2.2.28+6ced4dd919
			fabric-events-interaction-v0: Fabric Events Interaction (v0) 0.7.13+ba9dae0619
			fabric-key-binding-api-v1: Fabric Key Binding API (v1) 1.0.47+0af3f5a719
			fabric-networking-api-v1: Fabric Networking API (v1) 4.3.0+c7469b2119
			fabric-resource-loader-v0: Fabric Resource Loader (v0) 1.3.1+5b5275af19
			fabric-screen-api-v1: Fabric Screen API (v1) 2.0.25+8b68f1c719
		dynamic_fps: Dynamic FPS 3.11.3
			net_lostluma_battery: battery 2.0.0
		entity_model_features: Entity Model Features 3.0.10
		entity_texture_features: Entity Texture Features 7.0.8
		fabric-api: Fabric API 0.116.8+1.21.1
			fabric-api-lookup-api-v1: Fabric API Lookup API (v1) 1.6.71+b559734419
			fabric-biome-api-v1: Fabric Biome API (v1) 13.0.31+d527f9fd19
			fabric-block-api-v1: Fabric Block API (v1) 1.1.0+0bc3503219
			fabric-block-view-api-v2: Fabric BlockView API (v2) 1.0.11+ebb2264e19
			fabric-blockrenderlayer-v1: Fabric BlockRenderLayer Registration (v1) 1.1.52+0af3f5a719
			fabric-client-tags-api-v1: Fabric Client Tags 1.1.15+6573ed8c19
			fabric-command-api-v1: Fabric Command API (v1) 1.2.49+f71b366f19
			fabric-commands-v0: Fabric Commands (v0) 0.2.66+df3654b319
			fabric-content-registries-v0: Fabric Content Registries (v0) 8.0.19+b559734419
			fabric-convention-tags-v1: Fabric Convention Tags 2.1.6+7f945d5b19
			fabric-convention-tags-v2: Fabric Convention Tags (v2) 2.11.2+fa89716719
			fabric-crash-report-info-v1: Fabric Crash Report Info (v1) 0.2.29+0af3f5a719
			fabric-data-attachment-api-v1: Fabric Data Attachment API (v1) 1.4.6+5b36e0f719
			fabric-data-generation-api-v1: Fabric Data Generation API (v1) 20.2.35+37516cd619
			fabric-dimensions-v1: Fabric Dimensions API (v1) 4.0.1+65213ef819
			fabric-entity-events-v1: Fabric Entity Events (v1) 1.8.0+2b27e0a419
			fabric-game-rule-api-v1: Fabric Game Rule API (v1) 1.0.53+6ced4dd919
			fabric-item-api-v1: Fabric Item API (v1) 11.2.0+3b3cb2e819
			fabric-item-group-api-v1: Fabric Item Group API (v1) 4.1.7+def88e3a19
			fabric-keybindings-v0: Fabric Key Bindings (v0) 0.2.45+df3654b319
			fabric-lifecycle-events-v1: Fabric Lifecycle Events (v1) 2.6.0+0865547519
			fabric-loot-api-v2: Fabric Loot API (v2) 3.0.15+3f89f5a519
			fabric-loot-api-v3: Fabric Loot API (v3) 1.0.3+3f89f5a519
			fabric-message-api-v1: Fabric Message API (v1) 6.0.14+8aaf3aca19
			fabric-model-loading-api-v1: Fabric Model Loading API (v1) 2.1.0+b4d813fc19
			fabric-object-builder-api-v1: Fabric Object Builder API (v1) 15.2.1+40875a9319
			fabric-particles-v1: Fabric Particles (v1) 4.0.2+6573ed8c19
			fabric-recipe-api-v1: Fabric Recipe API (v1) 5.0.15+2475392c19
			fabric-registry-sync-v0: Fabric Registry Sync (v0) 5.3.1+e3eddc2119
			fabric-renderer-api-v1: Fabric Renderer API (v1) 3.4.1+b4d813fc19
			fabric-renderer-indigo: Fabric Renderer - Indigo 1.7.1+c705a49c19
			fabric-renderer-registries-v1: Fabric Renderer Registries (v1) 3.2.69+df3654b319
			fabric-rendering-data-attachment-v1: Fabric Rendering Data Attachment (v1) 0.3.49+73761d2e19
			fabric-rendering-fluids-v1: Fabric Rendering Fluids (v1) 3.1.6+1daea21519
			fabric-rendering-v0: Fabric Rendering (v0) 1.1.72+df3654b319
			fabric-rendering-v1: Fabric Rendering (v1) 5.1.0+ab4c25a019
			fabric-resource-conditions-api-v1: Fabric Resource Conditions API (v1) 4.3.0+8dc279b119
			fabric-screen-handler-api-v1: Fabric Screen Handler API (v1) 1.3.90+b559734419
			fabric-sound-api-v1: Fabric Sound API (v1) 1.0.23+6573ed8c19
			fabric-transfer-api-v1: Fabric Transfer API (v1) 5.4.3+c24bd99419
			fabric-transitive-access-wideners-v1: Fabric Transitive Access Wideners (v1) 6.2.0+45b9699719
		fabric-language-kotlin: Fabric Language Kotlin 1.13.8+kotlin.2.3.0
			org_jetbrains_kotlin_kotlin-reflect: kotlin-reflect 2.3.0
			org_jetbrains_kotlin_kotlin-stdlib: kotlin-stdlib 2.3.0
			org_jetbrains_kotlin_kotlin-stdlib-jdk7: kotlin-stdlib-jdk7 2.3.0
			org_jetbrains_kotlin_kotlin-stdlib-jdk8: kotlin-stdlib-jdk8 2.3.0
			org_jetbrains_kotlinx_atomicfu-jvm: atomicfu-jvm 0.29.0
			org_jetbrains_kotlinx_kotlinx-coroutines-core-jvm: kotlinx-coroutines-core-jvm 1.10.2
			org_jetbrains_kotlinx_kotlinx-coroutines-jdk8: kotlinx-coroutines-jdk8 1.10.2
			org_jetbrains_kotlinx_kotlinx-datetime-jvm: kotlinx-datetime-jvm 0.7.1
			org_jetbrains_kotlinx_kotlinx-io-bytestring-jvm: kotlinx-io-bytestring-jvm 0.8.2
			org_jetbrains_kotlinx_kotlinx-io-core-jvm: kotlinx-io-core-jvm 0.8.2
			org_jetbrains_kotlinx_kotlinx-serialization-cbor-jvm: kotlinx-serialization-cbor-jvm 1.9.0
			org_jetbrains_kotlinx_kotlinx-serialization-core-jvm: kotlinx-serialization-core-jvm 1.9.0
			org_jetbrains_kotlinx_kotlinx-serialization-json-jvm: kotlinx-serialization-json-jvm 1.9.0
		fabricloader: Fabric Loader 0.18.4
			mixinextras: MixinExtras 0.5.0
		forcecloseworldloadingscreen: kennytv's epic force close loading screen mod for Fabric 2.2.3
		freecam: Freecam 1.3.0+mc1.21
		inventoryprofilesnext: Inventory Profiles Next 2.2.3
		iris: Iris 1.8.8+mc1.21.1
			io_github_douira_glsl-transformer: glsl-transformer 2.0.1
			org_anarres_jcpp: jcpp 1.4.14
			org_antlr_antlr4-runtime: antlr4-runtime 4.13.1
		java: OpenJDK 64-Bit Server VM 21
		knowlogy: Knowlogy Book 0.9.1
		krypton: Krypton 0.2.8
			com_velocitypowered_velocity-native: velocity-native 3.3.0-SNAPSHOT
		lambdynlights: LambDynamicLights 4.8.7+1.21.1
			lambdynlights_runtime: LambDynamicLights (Runtime) 4.8.7+1.21.1
				lambdynlights_api: LambDynamicLights (API) 4.8.7+1.21.1
					yumi_commons_collections: Yumi Commons: Collections 1.0.0
					yumi_commons_core: Yumi Commons: Core 1.0.0
					yumi_commons_event: Yumi Commons: Event 1.0.0
				pride: Pride Lib 1.2.4+1.21.1
				spruceui: SpruceUI 6.2.5+1.21.1
				yumi_mc_core: Yumi Minecraft Libraries: Foundation 1.0.0-beta.1+1.21.1
		lavender: Lavender 0.1.15+1.21
			lavender-md: lavender-md 0.1.2+1.21
			lavender-md-owo-ui: lavender-md-owo-ui 0.1.2+1.21
		libipn: libIPN 6.6.2
		lithium: Lithium 0.15.1+mc1.21.1
		malilib: MaLiLib 0.21.10
		mega_showdown: Cobblemon:Mega Showdown 1.6.2+1.7.2+1.21.1
		minecraft: Minecraft 1.21.1
		minihud: MiniHUD 0.32.60
		modmenu: Mod Menu 11.0.3
			placeholder-api: Placeholder API 2.4.0-pre.2+1.21
		mr_mega_showdownitempack: Mega Showdown Item Pack 1.4.2
		nochatreports: No Chat Reports 1.21.1-v2.9.1
		ok_zoomer: Ok Zoomer 10.0.0-beta.11
			wrench_wrapper: Wrench Wrapper 0.8.1
			wrench_wrapper_backend: Wrench Wrapper (Backend) 0.8.1
		owo: oωo **.**.**.**+1.21
			blue_endless_jankson: jankson 1.2.2
			io_wispforest_endec: endec **.**.**.**
			io_wispforest_endec_gson: gson **.**.**.**
			io_wispforest_endec_jankson: jankson **.**.**.**
			io_wispforest_endec_netty: netty 0.1.2
		patchouli: Patchouli 1.21.1-92-FABRIC
			fiber: fiber 0.23.0-2
		playerxp: PlayerXP 1.0.4+1.21.1
		rad-gyms: Rad Gyms 0.3.1-stable
			admiral: Admiral 0.4.10+1.21.1
		rctapi: Radical Cobblemon Trainers API 0.14.6-beta
		safepastures: Safe Pastures 1.1.1+1.21.1
		simpletms: SimpleTMs 2.3.3
		sit: Sit 1.21-28
		sodium: Sodium 0.6.13+mc1.21.1
		spawn_notification: Spawn Notification 1.7.2-fabric-2.3.0
		switcheroo: Switcheroo 1.0.14
		tim_core: Tim Core 1.7.2-fabric-1.30.0
		vinurl: VinURL 2.2.1
		waystones: Waystones 21.1.25
		xaerominimap: Xaero's Minimap 25.3.5
			xaerolib: XaeroLib 1.0.45
		xaeroworldmap: Xaero's World Map 1.40.6
		xmxw: Xaero's Maps x Waystones 2.3.4+1.21.1-fabric
		yet_another_config_lib_v3: YetAnotherConfigLib 3.8.2+1.21.1-fabric
			com_twelvemonkeys_common_common-image: common-image 3.12.0
			com_twelvemonkeys_common_common-io: common-io 3.12.0
			com_twelvemonkeys_common_common-lang: common-lang 3.12.0
			com_twelvemonkeys_imageio_imageio-core: imageio-core 3.12.0
			com_twelvemonkeys_imageio_imageio-metadata: imageio-metadata 3.12.0
			com_twelvemonkeys_imageio_imageio-webp: imageio-webp 3.12.0
			org_quiltmc_parsers_gson: gson 0.2.1
			org_quiltmc_parsers_json: json 0.2.1
	Loaded Shaderpack: ComplementaryReimagined_r5.6.1.zip
		Profile: LOW (+1 option changed by user)
	Yumi MC Core: 1.0.0-beta.1+1.21.1

Additional Information

I had reported this bug in another mod's issue tracker as I thought it was related to that mod, but after investigating a bit more, the bug appeared without the involvement of it.

https://github.com/alinco8/XaerosMaps-x-Waystones/issues/29

Edited Jan 27, 2026 by Nato Boram

Failed to decode packet clientbound/minecraft:custom_payload