**** I just got the same problem.
My colleague has a Lumia 800 which had the exact same problems had to be sent to repairs.
Why dont they fix these errors when they build new models?!!!!
This is my first big disappointment with my L920. :(
My phone was standing in a stand earlier today and when I was about to pick it up it fell forward hitting the front to my keyboard, no hard fall att all but maybe the sensor got screwed up by this?
Is there no way to test this like there was on WP7?