My roof looks just like that at each roof seam. I was told by manufacturer through dealer that this is not a problem. I was skeptical, but after 2 seasons, there is no change, so I'm not too concerned about it anymore.
I try to take good care of the roof, keep the ripples clean and avoid stepping on them.
Here is the thread I started when I first saw the wrinkles in my roof - http://www.forestriverforums.com/for...of-155699.html
I'm NOT saying it is or is not a problem. Just sharing my experience.