I finished quilting a charity quilt and trimmed the edges.

As I always do, I set a long, wide zigzag stitch to hold the edges together. It pulled together (like zigzagging a dress weight fabric to finish a seam) and added a little pleat to the backing and made the edge stiff.

Maybe it’s because I used polyester batting, instead of the usual cotton. I was just surprised it happened with all the layers. Thread was the same Robison-Anton cotton top and bobbin.

Have others had this problem? I pulled out the stitching and will just sew the binding on.