GPM drives me insane! Every single time have tried to use it (via the music on my phone or their streaming service) the player either freezes up, or 99% of the time if I play a tune then hit "next" it skips 2...3...4 songs for NO REASON! I would get so mad at it I'd disable it for months and use something else. The I'd think "Oh it has to be fixed now" so I try again, nope, still skipping songs for no reason.
I Googled the issue and low and behold there are a BUNCH of folks complaining about the same issue and Google never seems to be able to reply on their forum with what the fix is or what the issue is. This is why I refuse to sign up again for their $10 a month service, fix it, and I may be back. For now it's 100% Spotify for me.