Perfect binder kicks the cover a bit when it moves over paper--Help!

[Rpburchell]

Hi, all. Well, our D60c-A3 perfect binder is working pretty well, except the covers come off just a tiny bit lopsided. It looks like the get kicked out of place just a bit when the cover moves over the paper. Does anyone know of any fixes to this problem? It looks like some binders come with a magnetic bar to keep the cover straight, but ours does not have one...Thanks in advance!