i thought i was going crazy before, but this is a thing that's been the case since beta. 3.7.6 has broken added physbones on avatars, I switch back to 3.7.5 and the physbones function correctly. mind you, I am adding physbones to an avatar that has proper armature and weight painting. they do not move in play, and they in fact do not function in world. pls fix
This is merely an example;
  1. Drop in Odo's Foxxo Avatar
  2. Add a Physbone Component to the base prefab
  3. Map the root bone to Left Rear
  4. Adjust parameters to liking
  5. Enter Play Mode