crash-2021-03-21_21.53.57-client.txt
There is a crash report, my Minecraft version is 1.12.2 , Forge version is 2854.
I deleted one of the Auto Feeder Helmet or MMDLib, the problem has solved.
Can you fix it? then, I have reported it in MMDLib

We discuss it over at MMDLibs issue tracker: MinecraftModDevelopmentMods/MMDLib#68