Wow. I've used fleece on the back of a number of quilts - 3 T-shirt quilts and several other for family members (lap sized, not bed sized) and have had NO trouble with it. In fact, I thought that it laid much flatter and smooter than cotten when I am spraying the sandwich. I alwasy use spray - never baste or pin, and I've been very happy with the results. Maybe the difference is that on all the quilts I've used fleece I've just done SID quilting - no free motion.