I've had theis problem, found that the second bar back wasn't folding in sequence, so making sure the cloth was loosening between the bars , as you folded it worked, the top folded as it should. As a secondary assist for it, bought some 2" wide elastic strap, my wife sewed some velcro to a length of it, (short enough to put some pull between the bars) and made a loop between the second and third bars, which worked well.