BluWizard
In order to recreate this issue, you must update your SDK in Creator Companion with Unity completely closed.
  1. Close Unity.
  2. Update Avatars SDK from 3.5.0 to 3.5.1.
  3. Launch Unity.
  4. Go to a VRCPhysBone component or similar. In some situations, an Error will be thrown and the UI Instance will not load correctly (see screenshots attached). In this example, VRCPhysBone is not loading correctly.
This is probably an instance of Unity failing to load DLLs correctly. Since the VRC Phys Bone component is loaded from
VRC.SDK3.Dynamics.Phys Bone.dll
, Unity failed to load the instance of it correctly.
To get around this, you must manually click
VRChat SDK -> Reload SDK
in order to force Unity to recompile all the SDK's Scripts and DLLs. If successful, this problem will disappear and everything goes back to normal.