When using the MinecraftCapes mod and I have ears uploaded the rest of skin is weird.
https://modrinth.com/mod/minecraftcapes

This didn't use to happen in 1.21.8 but started in 1.21.9/10.

The ear texture seems to be copied to the players skin.

The ear texture comes from the skin and is, I assume, a feature from the minecraft capes mod. Not sure why the rest is off, looks almost like the texture is moved or something. Provide the skin, but I dont think there is any link between 3d skin layers and the minecraftcapes mod.