If the front wheels are in the way mine doesn't close all the way. Otherwise it closes fine. It's annoying but I've learned to just adjust it every time.
Mine has this issue sometimes, but I've noticed it can be avoided if I pull REALLY hard and quick on the handle things you pull to fold it. The issue only seems to pop up when I'm being lazy and don't give it all I've got (haha). When I make a point to do a hard, quick jerk to close it, it seems to close fully.
Re: Those with the City Mini Double: Closing it issues?