Bumper Issue
 

Hi group, I'm new here hope you can help. I own a black 2008 R class. Original owner, the only one who has ever driven it. Love the car never had an issue with it. 33,500 miles on it. However this past week I noticed what looked to be two small indentations or a paint blemish in the rear side bumper. The car has never been damaged. Nothing has hit it. It's on my passenger side rear upper side bumper right behind the wheel well. Looking at it close up you can't see it. You have to stand back. I notice it when I'm approaching the car. I removed the wheel well cover and reached behind the bumper. No dent felt. It seems the areas are located where there are no suports. Nothing behind it at all. I'm wondering if its from the sun wraping the bumper on hot days when its outside. Most of the time the car sits in the garage where I can't see any issue at all. But go shopping and come out from a store and there it is. Has anyone noticed this on their car? I've seen a few C class owners talk about the same issue but no ones posted a fix. It seems to only effect black cars. My car is babied and dosen't have a dent or a scratch. This is driving me crazy! The car is still under warranty, has anyone had Mercedes replace the bumper cover or found a fix?
Thanks!