After I unplug my phone from the charger, it works great for about 3-4 hours. Then, suddenly and for no apparent reason, the sound no longer works. I still receive calls, but no ringing. I can go to media player and it says that the media player is busy and will not play sounds. However, if I do a battery pull, the sound will be fine.
I have no problem with actually making/receiving calls or hearing the conversation, just no rings.
This also happens at random when I switch profiles... for example, if I switch from Silent to Normal. The profiles will show that Normal is active, but still no sound.
I have wiped my phone and gone a day without any additional apps and it still does it so I know it is not an app causing the problem.
It is still under warranty, but VZW is giving me a headache about it since I had to replace my 8330 less than a month ago (also under warranty and for a separate issue)