Title says it all. I am playing with forge and optifine on minecraft 1.12.2. All hats are green and only hues of green when shaders are enabled.

Closing all issues as Hats has been rewritten from the ground up and the old mod for a long time now was no longer supported.. I'm sorry I wasn't able to address your issue. If you're still playing modded Minecraft, consider checking out Hats for 1.16.5+.