Arc Spontaneous Random Reboots

So, I've had 5 random reboots so far today, including one that happened less than 10 minutes after I finally allowed my Arc to update to its latest Jelly Bean version (build no. JRO03L773, kernel 3.0.31, build@kb-bd-lin32-001 #1, May 7th)

Anyone else been getting them lately? :/

EDIT: Random reboot number 6...

EDIT 2: And that seems to be the last one. For now. Hasn't spontaneously rebooted yet today, though nothing on my system changed.