I ran into this issue today, and had to use SetSlotsToSetupPose() as well, but just curious about something.
I was working on a project just about a month ago, and I didn't have to use SetSlotsToSetupPose() after setting the skin. It updated on it's own. Just wondering if something changed in the backend, or I was lucky, or there is something that I can do in the skeleton set up to avoid having to call SetSlotsToSetupPose().
Thanks!