I have one where the Google Music app doesn't want to play music. I can browse the library but when I tap a song or playlist nothing happens. If I reboot the phone it will start working again but eventually stops working.
No it's the most immediate source from inside HTC. It's pretty much assured that we won't see it till April and I can only sincerely hope that as it was delayed a month they would bump it to 5.1. I'm not holding my breath though.