I've seen a couple of random reboots recently on my webOS 2.1 VZW Pre2. Once it happened while I was on a call, and once it happened while the phone was sitting idle. It's possible it happened other times and I just didn't notice. It's particularly disturbing, obviously, when it happens while on a call. I don't know if it's related (I suspect it is) but I pulled out my phone one day recently and found that I was logged out of EVERY app on my phone -- Foursquare, Facebook, Feeds Free, and even the stock calendar!
I haven't installed any new patches recently, so I can't figure out what's causing this all of the sudden. Has anyone else experienced this?