I've hand-quilted everything from batiks and lawns to linens and denim. The best way to test out your method + materials is to do a short run of stitches without any hoop/frame, fully manipulating the quilt to figure out how much force and what angle you need to drive the needle through multiple layers. (this also will tell you if it's sticking on the needle eye, thread, or just not penetrating because the point is bad.)
My guess is that it's a tension issue between how much stretch your fabric has and how tightly it's pulled on the loop. Small pieced tops like hexies can be deceptively thick and rigid do to all the seams, so you might need to loosen the quilt on the hoop so you can angle your needle a little higher on the downstitch.