I have no idea why it’s doing this or how to investigate it. This just now happened when the screen was already active and displaying a watch face and nothing else happened. I have a series 4 with the latest watchOS 9.2.
Apple Watch Series 4
First force restart the Watch
i.e. press and hold both the side button and Digital Crown for at least 10 seconds, then release both buttons when you see the Apple logo.
Then, although it may seem irrelevant, Force Restart the paired iphone Force restart iPhone – Apple Support (UK)
If it is still misbehaving...
Unpair and erase your Apple Watch
and then
If no better you may want to unpair then set up without restoring the backup.
You may also want to make sure the software on the watch and iphone are up to date.
Update your Apple Watch - Apple Support
Update your iPhone or iPad - Apple Support
If you've completed that troubleshooting and the issue is still not resolved, Contact Support.
Click here > Contact - Official Apple Support
or phone numbers
Click here > Contact Apple for support and service - Apple Support
But none of that diagnoses the problem. How do I figure out why it's happening or whether I've "erased" it if it happens entirely at random and I can't reproduce it at all? This only happens every few days to every few months, so I have no idea. Thank you for your help though.
If you do all that and it still does it then the Watch needs repairing, hence the last link. You will probably never know why, it would probably be a hardware problem.
If it stops doing it then the reinstall has fixed it.
How will any of this help me solve my problem?
That is the entire diagnostic process for any unusual behavior. Work through it.
There are links for Apple Support if nothing works.
Why is my Apple Watch buzzing my wrist when there are no notifications?
