I've recently been experiencing an issue with my Xperia xz where the volume turns itself right down to 0 (for both media and notifications) when I have earphones in. I never put the phone in my pocket when I run, and I actually watch it pull the volume back down when I turn it back up. When it's doing this I also can't use the volume buttons on the side of the phone and can only bring the audio back up by using the screen. With the notifications, it not only sets it to vibrate but activates the "Do Not Disturb" function as well. Restarting seems to be the only way I can get the phone to behave normally again.
