[Q] Reboots every evening after getting 4.2.2 update topic

OK, this is really weird - after getting the 4.2.2 update, my phone reboots itself every night, not 100% sure it's exactly the same time, but it's been while sitting in my pocket or on the table, not even in use. At first I assumed it was Zooper, which I had installed right after the update, but I disabled it yesterday and got the reboot again tonight.

I even checked my Tasker to make sure some auto-reboot profile hadn't installed itself!

Any hints about how to diagnose this? Do I have no choice but to remove apps one by one? Most of the apps I run are the same ones I run on my TF300 tablet which also has 4.2.2, so don't know if it could be an app.