Comment 53 for bug 1521987

(In reply to Tanu Kaskinen from comment #24)
> Do you happen to have the audio settings application open? If you do, it can
> mess up the device selection:
> https://bugzilla.gnome.org/show_bug.cgi?id=762932

It happens when audio control application running and not running likewise, but desktop's audio widget in the panel is indeed running (Cinnamon and Unity, same manifestations). It is possible that this audio widget is indeed the culprit.