Ring volume keeps reseting to zero I have a OnePlus X running Android 5.1.1.

I noticed that the ring volume keeps reseting itself (or is reset by s.t.) to zero. This usually happens when I switch the phone back from no-interruptions mode but also at essentially random moments (if much more rarely then).

Is there any way to stop this?
My Problem is Solved by upgrading Android lollipop to marshmallow 6.0.1.