Couldn't save chunk; already in use by another instance of Minecraft

Describe the bug

When i save new arena it console spam and crash server.

How to reproduce

setup new arena and save it

Expected behavior

no crash, and console behavior normal

Server info

• Plugin version: ... (Write the complete version string. Do not say latest)
• Server version: 1.15.2
• Server log: ... (Use pastebin) i cant use pastebin over 512 kb, i attach a file.latest__1_.log