Hello !

Mod Loader (Required)
Forge

Minecraft Version(s) (Required)
1.20.1

Mod Version(s) (Required)
SubtleEffects-forge-1.20.1-1.9.2
MutantMonsters-v8.0.7-1.20.1-Forge

Notes (Required)
Setting a a mutant skeleton on fire and killing it near water makes its part take fire, and when they touch the water the game indefinitely freeze
I made you a video to understand the issue :
https://streamable.com/ozv30s

This happened on the legendary edition modpack but it works with the subtle effects + mutant monsters mods alone too

latest.log (Required)
https://mclo.gs/qEC7fVw

Sorry there is no crash report on this that generates but the video will pretty much explain it all, you can try downloading mutant monsters and killing a skeleton on fire