Haven't had this happen before in the 2+ years I've had a 1030. During this morning's ride (just recording a ride, not navigating), I noticed that the Gear Combo field that shows the F/R eTap cogs in use had suddenly stopped showing any data, though other fields such as speed, distance etc were still functioning, and shortly after that the 1030 just powered itself down - battery level at the time was around 70%. I pressed the power button, the 1030 booted up, and displayed the save/continue activity screen. I pressed the start activity button and the unit continued as normal.
When I installed FW 10 on the 1030, I performed a full reset on the device, so there shouldn't have been anything from the previous beta FW left around.