Keeps vibrating 10-20 seconds

Another owner just told me elsewhere hers started doing the same thing since 16.xx update.

After some more testing, there's a pattern. It vibrates when I start a Health Snapshot. If I immediately stop it and start over, it doesn't vibrate. If I start a new one very quickly after the last, it doesn't. But if I wait, say an hour, it vibrates again.

After 18.22 was installed yesterday, I synced a few hours later, then restarted the watch. At bed time I tried to do a Health Snapshot as per usual. It vibrated four or five times before I got one start of Health Snapshot that didn't vibrate. Unfortunately one of the times I stopped the HS, it triggered morning report, minutes after I'd put my head on my pillow, so HRV reading was cut off. I manually started sleep mode, but it wasn't enough to get HRV to record for the whole night.

I was able to live with it before, but this is no good!

It happened again. The morning report got triggered when I went out of the Health Snapshot because of the buzzing. I will leave it on, hoping the HRV status doesn't get cut off.

But this is impossible! I need to see recovery time after Health Snapshot, and now I can't!

I lost only one hour of HRV data this last night, but I had no access to any screens until the morning report timed out. I don't know when that happened.

Exact same thing happened to me, on 18.22. Initiated a health snapshot at night, with watch already in Sleep Mode (triggered automatically). Got the continuous buzzing, stopped the snapshot, did another snapshot, and a morning report was launched as if I had awakened in the morning lol. 

This is what a normal night looks like:

I've changed the schedule to an hour later than I actually go to bed, and that way avoid triggering the morning report. That has issues too, so this is something that should be looked at either way.

I haven't had this now on 19.18 so maybe it's fixed?. I'll report back if it does happen again.