Apparently this is some kind of incompatibility with the engine?
embeddiumplus-1.20.1-v1.2.13.jar
Kiwi-1.20.1-forge-11.6.2.jar
PuzzlesLib-v8.1.21-1.20.1-Forge.jar
cullleaves-forge-3.2.0.jar
CullLessLeaves-Reforged-1.20.1-1.0.5.jar
Fallingleaves-1.20.1-2.1.0.jar
LeavesBeGone-v8.0.0-1.20.1-Forge.jar

[18:15:04] [pool-4-thread-1/WARN] [mixin/]: Method overwrite conflict for m_6104_ in embeddium.mixins.json:features.options.render_layers.LeavesBlockMixin, previously written by me.srrapero720.embeddiumplus.mixins.impl.leaves_culling.LeavesBlockMixin. Skipping method.