I have a 15 and noticed it as well. I have also noticed a pronounced bubble starting to appear. I went to the dealer and was told, sorry out of warranty, got the same response from another dealer. I purchased my 15 suburban for looks, style and the roominess, Not many choices that offer the things that I desired. I have always loved the GM suv line up. I am not pleased but I have to be honest I would still probably purchase another. Its all about the botton line. I love mine but, GM s customer service is lackluster at best. Its like everything else some dealers are better than others.