I have APQS Millenium, I don't know if that makes a difference, but I zipper to my leaders and took one quilt off 3 or 4 times to do other things without a problem. Here's what I do.
I would suggest unloading the whole quilt. Then check for wonkiness by laying it out on floor. If areas have stretched starch and steam and press them until you are square (or close) again. Reattach to the take up roller and roll up to where you ripped out. Then reattach only the backing to your front roller (partial float). Slowly roll up the backing fabric making sure there are no wrinkles or puckers. You will need to flip up batting and top out of your way. It's easier with 2 people. Do not roll top or remaining batting on any rollers. Flip fold the batting so you can gently work it right over the backing fabric (might need to loosen backing for slack) and under the roller for the top, letting excess drop to floor. Follow the same process for the top. Smooth top to feel for any wrinkles in batting or backing. Tighten backing roller, baste sides of top and proceed to quilt. Hope this helps you.