Could be the flange I guess, wiggle the carb at idle and if the idle speed changes you got a problem with the flange.
Dunno if it could be the stage 2 unit, no idea what the symptoms are if it isn't working

It could still be carb icing, how badly occurs depends on the conditions and how bad the anti icing systems are broken. For me it was random, sometimes happening on long jorneys, sometimes it would cut out at junctions.
It could also be something in the ignition system breaking down when the engine gets hot, leads, cap, rotor arm, coil etc
