Heavily starching the backing fabric and spray starching the top before layering pretty much prevents this problem. It stabilizes the fabrics so they don't stretch.
Once the quilt is already layered, applying multiple layers of spray starch to top and bottom will help a lot. Lay the quilt sandwich on a larger sheet to catch any overspray. Mist and let dry, mist and let dry. A fan will speed drying.
The tucks are caused by slight stretching of the fabric, even with the walking foot. Starch prevents this stretching.