Hello!

I appear to have run into a bug on 1.21.4 where this mod crashes the game whenever attempting to render the textures for a Wither Skeleton Skull, whether it is in the player's inventory or a chest. If the skull is in the player's inventory or chest, the game crashes as soon as the respective storage option is opened, and if the skull is in the hotbar, the game crashes immediately upon loading into a world.

I am currently running the game on Fabric 1.21.4 with other mods installed, all client side. No other currently installed mods and/or resource packs should be affecting the skulls, but I am happy to provide a list of them and/or any crash reports generated during troubleshooting if you think it will be helpful.

This was fixed a few hours ago, update the mod.