the warping look, actually isn't warping.

The walls curve in at each support,not perfectly straight. the one pic posted with the slight flap loose, there are about 3 more about 4 inches long in areas I can see.

I just don't know if its extra material at the edge of seam that wasn't fully bonded.Wish I knew how much material overlay they used to seam.Never thought about it when the pool co. installed.