I've seen a lot of discussion here in the forums around the 970 rebooting due to assistant access but not seen this one yet.
I've found that if you record multiple different activities while listening to music, the watch will reboot. This happens every time.
Here's the scenario today:
- Recorded a 2-mile run.
- Cooled down, recording a mile walk.
- Kicked off a bike ride.
- Watch rebooted.
Fortunately, after reboot the bike ride was still in progress (it started where it left off), but a couple reboots before it didn't do that.
These activities were being stored directly on the watch, i.e., I left my phone at home.