lubricate it with silicone (in the track) or get it replaced. I am afraid this is a dealer part, but if this is the case...call Acura of Augusta 800 736 6818, ask for Lisa or Jason and tell them the Legend Forums sent you.
Be prepared to pay around $80-$90 per side for the front, and $75-$80 for the rear, if needed.
Why so much? This part is an integral part of the door/window setup...not just where its cracking at....so best bet, for the short term is to lower the window, lube it, and guide it up and down in the track, and it will stay in there.