Not really sure if it's the real cause but imma just post it here.

Log: https://mclo.gs/uzY093g
Info like the modlist and version shown inside should be enough.

Try removing LoliASM and see if it still persists

i've downgraded mixinbooter to 7.1, solves the problem. i wonder which method is considered better as for now?

Did my suggestion work?

No, not working. Using MB 8.4 without LoliASM, what's even worse is that the game seemed to be ignoring MB, Dependency Missing pop-up was shown. I checked the jar to make sure it's not corrupted.

Log for that run?

2023-08-22-4.log.gz
debug-3.log.gz

Race condition troll
Put MixinCompat down 1

Actually, can you send me the instance so I can test it
Minimal if possible

@KorewaLidesu Here it is, basically just mods and config folder so you can simply create a 1.12.2 instance and drag them in. https://mega.nz/file/gQgEmBga#H6Fd-b1izbmutDU44OEhQSpSRLoYLHdxn66m14A9Z6o

Is this still reproducible? @ChromaPIE @KorewaLidesu

No crash of this kind with the latest version of the mods mentioned. fine for me to just close it.