Client Version: 1.18.2
Changed Version used: 0.12.1
Forge Version: 40.2.10

Crash message in short to save space:
Cannot invoke "VoxelShape.m_83281_()" because "this.f_60842_" is null at BlockBehaviour.BlockStateBase.Cache (line 838)
at BlockBehaviour.BlockStateBase.m_60611_ (line 454)

It seems to be triggered by this call "this.collisionShape.isEmpty()" at line 838 in BlockBehaviour.BlockStateBase.Cache class.
My personal guess is that some mixins from other mod prematurely returned "block.getCollisionShape()" at line 837 with a null value, which sat this.collisionShape to null and thrown this exception.
Do you think it would be helpful if you can make another mixin for Cache class?
[@mixin(targets = "net.minecraft.world.level.block.state.BlockBehaviour.BlockStateBase.Cache") long name since its a package only class, injected at the constructor, and at = @at(value = "INVOKE_ASSIGN", target = "getCollisionShape") to check if the field is null and set it to Shapes.empty() if so]
(I'm not very familiar with mixins so it might be wonky)
Or is it the Mixin Priority? just guessing here