Watch Firmware Updates Failing

I think the problem is related to 47 vs 47c.

47 successfully updates to the latest firmware, 0.12.49.

47c is stuck on 0.12.28.

Is there an internal difference between 47 and 47c that requires separate firmware?
If not, can 47c users reset their watch, add watch as 47 and load 0.12.49 with no issues?