I agree, there is to much "shoulder" in the luff entry in the top third or so. This reduces the angle of attack of the kite to a very small margin, and the bottom of the luff has an entirely different entry giving it a much wider set of angles at which it will work -it should be like trying to set two kites of different cut from the same points at the same time - not easy. Only conclusion that I am aware of is to recut the luff entry.