Nothing of the above solved ir for me, in my case only spoty goes mute after pause, all the rest keeps working just fine. It seems like, to me at least, it looses track from which device i'm listning from, to get it working back again I have to open the webplayer and click the device i'm listing from at the bottom righ menu, hope it helps! By the way this happens on windows player (running win10 Enterprise 1803)
That has nothing to do with Spotify. I recently had the same issue.
This is caused by the feature of AVRCP (Controling music via media keys on the headset/earphone). You have to simply disable the corresponding AVRCP Driver of your bluetooth device in the Windows Device Manager. For example see the attached screenshot.