mine dun have volume problem but while listening to music, occasionally it will pause a second or two like there is some notifications come in but when i checked, nothing. 

notice the screen will dim itself sometime if i am reading some web page or even tried just at the homescreen. I did not use auto brightness and set the Screen Mode to standard/pro photo, still same auto-dimming (battery life more than 70%).  Did i miss any setting? 

i have hell lot other minor issues too.  Just did a factory reset 1 hour ago, decided to do it sooner than later since got some spare time now.  Thanks God, so far everything seems perfect already, before i start restoring from Helium.  You may want to try a factory reset too.