Speaking as a very much relative Harrier Ignoramus compared to the above exhalted company a question nonetheless comes to mind reading what's been said already. Is the problem not wing lift, so much as that the airflow in which the jet is operating in jetborne or semi-jetborne flight is perhaps affecting the efficiency of the engine, either through causing a certain amount of warm efflux to enter the intake, or by affecting intake and thus compressor efficiency?
G