I’ve got a rigidbody attached to a bone in an animated mesh. The rigidbody is kinematic, has no translational or rotational drag, and is not using gravity. Its collider is a trigger. No scripts ever reference its position or velocity. It should never ever move unless it is moved by the animation, right?
Then why does it sometimes drift away from the rest of the mesh?
I don’t know about the rest of it, but why are you using a RB when you are just using it’s collider as a trigger? You can do that without a RB, otherwise it defeats the purpose of a RB in the first place. Unless I am missing something. 
-Jeremy
Yeah, sorry, I should’ve explained why I want a rigidbody that doesn’t do anything. Its because triggers need a rigidbody in order for Unity to detect when they touch something by moving into it. Without a rigidbody, the trigger will only detect things that move into the trigger.
Ah, right, forgot about that issue.
Still don’t know why they are moving. You are sure you are not resetting the isKinematic flag from code somewhere?
-Jeremy