[17:53:39] [main/FATAL]: Mixin prepare failed preparing IdentifierMixin in astromine.mixins.json: org.spongepowered.asm.mixin.transformer.throwables.MixinTargetAlreadyLoadedException Critical problem: astromine.mixins.json:IdentifierMixin target net.minecraft.class_2960 was loaded too early.

[17:49:41] [main/FATAL]: Mixin prepare failed preparing MixinSharedConstants in sectionsign.mixins.json: org.spongepowered.asm.mixin.transformer.throwables.MixinTargetAlreadyLoadedException Critical problem: sectionsign.mixins.json:MixinSharedConstants target net.minecraft.class_155 was loaded too early.

Removing ConveGrief fixed the issue

This is due to line 19 of MixinConfigPlugin. Referencing Minecraft classes from a mixin config plugin causes a LOT of issues.

Couldn't reproduce for some reason but should be fixed anyway