How we can reproduce it using the example you attached

1. Make sure you have 2d Animation Package
2. Open Scene with your Sprite Prefab that has Bones, geometry and weights painted.
3. Note that Game object is a Prefab, go into prefab mode and move the bone
4. Note that Sprite does not seem to update itself when posing bones in Prefab mode

Additional Note: The Sprite will still be updated in Scene View