I have an animated fbx skinned mesh that I am applying muscles to. When I add a muscle and turn jiggle on, it goes a bit crazy at the start of the animation, then calms down. I had this with complicated rig so I tried a simple setup and got the same problem. Any ideas what might cause it?

I'm also finding that the collect_centers python node for the muscle skin displacement doesn't collect the muscle wires properly. They're way too big. I'm wondering if the two issues are connected.

I've attached a file to demonstrate the issues.