Skype running in background makes all sound controls inoperable

I have had this problem for a few days - all sound controls for anything, even with the headphone controls have no effect. The volume bar goes up and down but the sound stays consistently low, with no change. Even the phone button and ring sounds are low.

And then I figured out all this happens while running skype in the background. If i quite skype then everything works as it should. Is this a skype problem or an iIOS problem?