I have a Series 0 Apple Watch Sport.
When an alarm is going off my Apple Watch no longer vibrates. All other haptic feedback (prominent or not) is working fine.
I had this problem for every watchOS beta so far, but it was never fixed. Now that the GM is out, I have to assume it's an intentional change (?)
This is kind of frustrating, because my main use case for the watch is the silent alarm 😟