Sorry, my java skills are kinda meh, but I did notice this line in particular. Caused a crash when in the nether. Not exactly sure why it happens or what triggers it, I was in the nether for a little while before this happened. I was just running around and everything froze.

{re:mixin,pl:runtimedistcleaner:A,re:classloading,xf:fml:astralsorcery:sun_brightness_client,pl:mixin:APP:architectury.mixins.json:MixinClientLevel,pl:mixin:APP:abnormals_core.mixins.json:client.ClientWorldMixin,pl:mixin:A,pl:runtimedistcleaner:A}

Full crash report here ---> https://pastebin.com/RBiVVF40

If it helps, I do have two mods that take over nether biomes: Biomes o Plenty and Oh the biomes you'll go. Both provide biomes for the nether dimension. Not sure if the gen type affects anything. Seems to only be affecting in the new version of astral sorcery (1.13.12). Tested on forge 36.1.25.

EDIT: re-enabled chocolate fix and got a new error, still points to this mod and the coremod :/
https://pastebin.com/sZ6H3MKQ

Ok, at this point, I have no idea what is actually causing this. Could be forge itself conflicting with these mods. Will leave open in case anything comes of it. Sorry if this is confusing.

Closing, as this appears to have been a mod interaction bug.