Reset issue I think i might have seen one other person mention.
There are users who get random restarts. However, only two mentions so far (including yours) of factory reset.
No idea why it would happen.
When it went back to "factory settings", what version of the software did you end up with? Did you check? Am just wondering if you actually got a borked update instead. (Given the timing of your problem, and the problems others are having with the update, am wondering if they are related.)