I didn't take the time to review the 8900 posts to see if this is a common issue, but I figured I would share.
I bought my 60GT50 on May 25, 2012.
The TV was originally in my bedroom and was hardly used for 3 months and then wasn't used for the next 6 months while I was in Germany.
I came home from work yesterday and noticed what appeared to be burn in (see photo).
The TV was off all day while I was at work and was only used for an hour the night before.
I called Panasonic, and they said they haven't heard of this before and have escalated the issue. But before I got off the phone, they said they would do not warranty any burn in issues.
I ran scrolling bars for 2 hours and it is now gone. Not sure what would cause this or if anyone else has experienced this before.