I did the factory reset, but it still goes bad. You go to bed with 90% battery, and you wake up with it totally dead. After performing major CPR (plugging it in, power, vol down) it comes up with 26% battery.
I'd say it goes into a race condition, and then a kernel panic. Standard Linux stuff. At least the phone doesn't melt down. This happens every few days, so I hope they fix it soon. I'm sure millions of others must have this bug.
Update: Google snuck in a bug fix without me knowing. :) Good for them, who wants to know this shit? You can look and it is build krt16s.