I use the Google Play Music app, and sometimes when hit the "play" button, it looks like it is going to do something, then goes back to showing the "play" button, and trying this multiple times yields the same result. I also had an issue where I pressed play and it didn't do anything, so i just did something else...then 30 minutes later it started playing music. This is for music already downloaded to my phone. A force close doesn't fix the issue, only a phone restart. The non responsive playing issue happened on both my G4 and G4P. The 30 minute lag thing happend on my G4P.