Yes, i have been facing the same issue as well ever since i updated my device to 10512 build, quiet hours in notification area doesn't go off. It keeps blinking & battery heats up too. Have turned off all the background apps and checked this whole thing again but the battery doesn't cool. Have gone through Cortana settings to find this option but nothing found. Microsoft, please keep a check on it and come up with the best resolution ASAP.. Or please let us know if anyone has an option to turn quiet hours off?