iPhone 5 controls get messed up when playing local files on spotify app

[Odaight]

Quite a specific problem that I have but inconvenient nonetheless.

If I play local files on my spotify app (iPhone 5, iOs 6.1.3, Spotify 0.6.3.16), press stop and exit the application, the 'play' icon doesn't disappear from the status bar and the controls that should change the volume of the phone's ringer still control the overall volume just like the app was still on. It functions like this until I open the app again, search a song from the spotify library (not synced local file), press play and then stop again.

a problem with the app, phone or the guy holding the phone...?