Other devices stop playback

[HazzerW]

I have a family account.  We access Spotify through my wife's phone (Android), my phone (Android), my tablet (Android), my desktop (Windows 10) and Google Home.

If my wife or I cast a playlist to the Google Home speaker from one of the phones or the tablet (signed in, in our own names), and the other person turns off the screen on their phone or the tablet, or (sometimes opens an app on the phone or tablet) the playback stops.  If it is restarted, it is no longer being cast.