Watch vibration keeps reverting to silent

I have set my watch to vibrate when an alarm is going off by setting the alert volume to zero, silent mode on and septic alerts on and set to 'Prominent'.

It works as expected only for an hour or two. Meaning every notification or alarm send a prominent vibration with no sounds. However, after a few hours it keeps reverting to no vibration at all for any alarm as well as no sound. Meaning I miss all the alarms I have set.

What can be done to bypass this problem? This is obviously a bug. I want all my alarms and alerts to be sent as a prominent vibration with no sound without setting anything again.

Thank you