Odd Spotify Connect problem with Samsung M7

[silressi]

I have a curious problem with my M7:

When playing music through it using Spotify Connect it periodically silences itself, as if muted - it doesn't stop playing, if you look in the app the song is still playing and the volume slider still sits wherever it was (eg. half way), but no noise comes from the speaker. If you adjust the volume at all it instantly carries on as normal. This happens seemingly randomly, can be after 5 minutes, can be an hour etc. Doesn't matter if your using the iPad app, Android app, PC program, same problem.

To me it would seem to be a hardware problem with the capacitive volume or mute switch on the speaker - but it doesn't do it when streaming TuneIn radio or from my PC.

Thoughts?