Hello, sorry to bother you.
I've been having issues with the Capuchin monkeys.
They seem to selectively stop functioning at random moments.
I've tested it with a total of 7 monkeys so far, and only the first monkey listens to commands properly.
The other 6 don't seem to move from the spot they were initially tamed on.
What I mean by this, is that six monkeys can't be made to follow or wander, but they do sit when told to do so.
A player can also not pick up these monkeys and walk away because after walking away wih the monkey on their shoulder from the original spot, eventually the monkey disappears from the shoulder and either respawns on the block where it originaly was tamed on, or outright vanishes entirely.
Reloading the world and game does not solve the issue. and I can't figure out why one monkey works and the others do not.

Minecraft version 1.16.5
Forge version 36.2.33
Citadel version 1.8.1
Alex's mobs version 1.12.1

Performance mods used:
Rubidium
Performant
FerriteCore
Helium
Radon

The bug is still reproducable even without any performance mods installed.