Vivec St. Delyn Upholsterer's Guild or assertion in recordptr.hpp (or compiler/linker flags used) causes failure?

Hello, friends!

On my Gentoo system I've built and installed the dev build of OpenMW, and I installed the MOMW Tools Pack.

With the expanded-vanilla list, upon running

./momw-configurator-linux-amd64 config expanded-vanilla --run-navmeshtool --run-validator --verbose --dev

I get the following:

[22:09:05.314 I] Processed interior cell (9234/10149) Ashur-Anit, Abandoned Temple with 394 objects
[22:09:05.317 I] Processed interior cell (9235/10149) Ashur-Anit, Hidden Passage with 229 objects
[22:09:05.324 I] Processed interior cell (9236/10149) Ashur-Anit, Triune Shrines with 506 objects
[22:09:05.344 I] Processed interior cell (9237/10149) Vivec, St. Delyn Carpet Layer's Guild with 285 objects
[22:09:05.374 I] Processed interior cell (9238/10149) Vivec, St. Delyn Upholsterer's Guild with 338 objects
openmw-navmeshtool: /var/tmp/portage/portage/games-engines/openmw-9999/work/openmw-9999/components/nif/recordptr.hpp:57: void Nif::RecordPtrT<Nif::NiAVObject>::post(Reader &) [X = Nif::NiAVObject]: Assertion `ptr != nullptr' failed.

Compiler used: clang

CFLAGS used in build: -O2 -march=alderlake -pipe -mno-cldemote -mno-kl -mno-sgx -mno-widekl -mshstk -fstack-protector-strong -fomit-frame-pointer -flto=thin -fPIC

LDFLAGS used in build: -fuse-ld=mold -Wl,-O2 -Wl,--sort-common -Wl,--as-needed -Wl,-S -flto=thin -Wl,--icf=safe -Wl,-z,rewrite-endbr

Output of openmw --version:

[22:21:49.610 *] Crash handler installed
OpenMW version 0.49.0
Revision: 63e3b8f41b

I can try recompiling without --icf=safe -Wl,-z,rewrite-endbr first and see if that fixes it, being that those are some of the more odder flags.