Charged my watch this morning, just noticed it had turned itself off. It was fully unresponsive to button presses (long press of light didn't reboot). HR lights were on until I fully took it off my wrist, then they turned off as well. Putting it back on the charger turned it back on. However, it is rather annoying that it needs this.
Software 20.26. When I selected check for updates, a download did start, but I'm not in beta, and it didn't really do anything...