My HTC Desire started doing that a few times a day at which point I replaced it. I think it was due to temperature because if I took it immediately from my jeans pocket and fired up some demanding app (network usage+CPU intensive) it would reboot almost immediately.
My Optimus 2X has done that on a few occasions, when I was messing around with modded ROMs etc. Now I just use the stock LG ICS ROM (rooted) and it's very stable.
My Optimus 2X has done that on a few occasions, when I was messing around with modded ROMs etc. Now I just use the stock LG ICS ROM (rooted) and it's very stable.