Yes Harrison it is what I meant.But squeeze the flap trailing adge and the one of the upper half of the wing with two fingers.One from up and one from under.Do it in the middle of the flap length.
So look at the flap/upper half edge holding the model horizontal ( keeping these parts squizes of course) Pay attention to areas where there are any gaps.between these edges.I think that the main problem can appaer at the wing - fuselage trasition.