When I pause Spotify, YouTube also pauses

[jamesduffy]

The "play/pause" buttons on Spotify and YouTube have somehow become linked. When I pause one, the other one pauses, and vice versa. This is very annoying.

edit: in fact, it affects other stuff too, like BBC iPlayer.

The problem only occurs when I'm using my bluetooth headphones (Bose). I've had them a year and never had this problem before.

I'm using Chrome (latest version). Restarting doesn't fix it.