Just had an issue where the screen would not time out at all after being plugged into AC overnight. Sometime yesterday, I changed the time-out from 30 sec to 3 min. Today I tried changing it back to 30 sec, but it still would not time-out at all, just stayed on always. I backed out of all running apps, made sure usb and any sensor areas were clean, and then did a power off and back on. Nothing. I finally went back and set the time-out back to 3 min, then home, and manually locked. Then went back in and reset time-out to 30 seconds. Fixed it.