I'm having a similar problem. I got a QFK kit and put it all together. When I went to sandwich it, I found that one of the borders wasn't cut right. It's narrower in one spot than the others (apparently that strip of fabric was cut crooked) and the way it's sewed on, the non-straight side was stitched to the quilt. So there's waviness. I'm debating whether to rip out the border and turn it around so the straighter side is sewn on but then I'll have to remove part of the top and bottom borders as well. At any rate I'll have to trim down all 4 borders because of this and the quilt won't be the right size but I don't have any of the same fabric and there's not much else I can do.