I've spent several hours today playing playlists and stations using Google Music on BubbleUPnP trying to replicate your problem but didn't have any issues with playback.
Anyone else having issues with Google Music?
Mmmm that's weird. I've even uninstalled BubbleUPnP and still have the issue aftewards.
I just have to select in fact any album or playlist, I get "Adding to playlist" and it's doing that forever.
Now when playing locally it works fine...
Rebooted the phone, reinstalled the app.
Note that I'm not in hotspot mode. But on my Wifi, with full signal.
I have no other choice to think that the issue is that new firmware since it was working perfectly fine before.
Any suggestions would be welcomed.