I've noticed the same thing on my 2011 Starcraft 235fb.
The grab handle by the side of the door has started to discolor and get black flecks in it. I've tried cleaning it with several things, including Mr. Clean Magic Eraser, but nothing works - it just looks dirty. We are in N. Minnesota so we don't have extremely high temps and the trailer is housed in an enclosed building about 6 months out of the year, so it doesn't sit out all the time.
Not a big deal to me, but interesting that someone else is having similar problems. So far, it doesn't seem to be deteriorating structure-wise, but maybe that is next?
