I received a replacement phone from Nokia due to the freezing issue. The replacement phone definitely has something loose inside. I think it's the battery too. I'm not sure if it's related but the replacement phone also seems to vibrate quite a bit when any sound is coming out of the phone at a reasonable volume level.
Needless to say ill be keeping my original phone and sending back the replacement :/
Wow, I did not expect that many people experiencing the same issue. In my case the battery is shifting with a click at the end if I move my hand or turn the phone upside down. Nokia "care"-less is taking a swing at my intellect and trying to convince me a moving battery is "by design". I asked for a confirmation of that statement so I can tweet about it.
Its the battery loose. Get it exchanged. This is what I had. All good so far.
I'm trying to, but I'm at the 2nd replacement (1st had a bad bluetooth chip in it) and ATT tells me there are 700 people in line for a refurbished yellow L920, and Nokia tells me my device is just fine and the moving battery will not impact the device performance.