I think Woody is right- it's the way the top folds that makes the marks on that section. I took this pick when I had the top folding down to see if it folded smooth like the plastic window top does, and it doesn't. Instead, due to the glass window, the fabric on the side has to fold sharply with creases, and thus, there are stress points at those creases. Mine still is holding up fine, but I do see areas where there will eventually wear thru.
