Did you ever get an answer for this? I've had the same issue twice now with UC when using my RM16AI on PC.
I contacted tech support and tried everything they suggested, but had no luck so I gave up and wirelessly connected to UC using a router and tablet. At least then I could control the mixer, but It is a pain when using the RM16AI as an interface. Because I can't control the input gain etc in Studio1.
Then, windows 10 updated and It worked fine again. However, recently there was another windows update and now I'm getting the same problem again.
So just wondering If you've had any luck?