Randomly, Animation Controllers referenced by scripts which are substantially changed can enter a state in which they completely ignore all parameter changes called from within the script using Animator.SetFloat() or .SetBool(), etc. Clearing the serialized Udon programs does NOT fix this issue. The only fix I’ve seen so far is to completely delete the animator controller AND its animations and remake them. Sometimes it takes multiple tries before it works again. This issue does not occur on Avatars, only Worlds. There is no console output when it fails in client sim. No idea when this started, probably years ago, but I think I started to notice it more over time as a consistent issue because I’m updating scripts with existing animations more often recently. This is a hard issue to recreate without an existing world with existing systems in it, so it may have gone unnoticed.