I ran into a bit of this myself, but just opened up the slot a very little bit. When I clecoed the detent bracket in place I found a slight rub on one side with the handle forward and a little rub on the other side with the handle aft. I took the detent bracket apart and ground the inside surfaces down in the areas that were rubbing. It only required a few seconds work with my pneumatic disc sander (super handy tool for this type of thing) and all was good. I notice that there is a very tiny bit of side to side play in the flap handle and consequently the potential for rubbing if I push to one side or the other. I think I'll probably put some thin UMHW tape on either the inside of the bracket or wrap the handle with it so that nothing gets beat up over time.