Mine just started doing this several weeks ago. Whenever I power back up my ringer is muted and it resets notification, ringer, everything to something different..not the default tones either. I've set default as the same thing and it still goes to completely different sound.
Just thought of something..before I pull the battery and power back up..I always clean out cookies and cache and system clean..but I've always done that...
but its a thought
