Happened to me once or twice as well. As usual I was in a hurry to actually try to look at it. Did what I had to do, next time I used the car, it was back to normal. I think in my case it was showing up blank screen.

I am a little irritated of the problem, but it hasnt been constant nor I really did have time to take a picture of the problem.

I also on occasion have other minor glitches.
1. Standing (parked) in NYC in between tall buildings and Navi by itself started to show as I am slowly drifting into the ocean. Within half hour I was half way to Nova Scotia... After I started to move it was still drifting for another 5-10 min.
2. Incoming phone calls at least twice came in, but I wasnt able to communicate with the other party.
3. MP3 CD was taking a long time to read on about 3 occasions and once didnt read untill I reloaded it.

Few minor bugs, nothing made me run to the dealer, but it is annoying and if it continues, I will start keeping a log and documenting things with pictures, etc.

Still dont condier it a lemon because the issues are minor and have not really disrupted my day/commute.