Hmmmm. My driver's door has been more difficult recently, due to it becoming almost totally frozen shut in the recent cold snap (when it was -8, brrrr!). I need to remove the doorcard and check the door pull inside as I think I've pulled it out of alignment a bit! Could be worth checking your passenger door in the same way?
Also, just to check - is it the interior door pull or the exterior door handle we are talking about here? My interior door pull on the driver's door does what you describe as a consequence of my first point
