Plane becomes unstable if GPS signal lost during acrobatic maneuvers

During high-speed acrobatic flight, my plane experiences violent pitching in ACRO mode, but not manual mode. I noticed that this happens when the GPS signal is lost due to loops, rolls and inverted flight. It appears that the p-gain increases if the GPS signal is lost, or the speed of the plane is not reported correctly. Is there a setting that controls this function? Seems like there is some gain compensation algorithm that is taking place, but it goes crazy if the GPS is lost. Please help.

Patrick Duffy

please upload your flight log