It depends if it was dropping a wing or not when it hits the stall, with it running out of adjustment on the vane, it could have been possible the angle of attack of the wing was wrong, that is why I suggested checking them to ensure they were set correctly, various things can cause problems, Rudder trim being one, flap rigging being another, you do get people tweaking the flaps on Cessna's to level the wings, however that is not the recommended path, it is on some Pipers hence why bad habits may slip across.