I have this message in the console:
defineId called for: class net.minecraft.world.entity.TamableAnimal from interface com.hollingsworth.arsnouveau.common.entity.IFollowingSummon

And this on my client:

I use Minecraft 1.20.1, Forge 47.3.12, Ars 4.12.6.all.

Please post the client log file

latest.log
I hope the latest log is that what you need.