After 20.1 I’ve noticed A/P is more weird than ever, during my descent (noticed on 772 and A320) as I extend flaps to max degree during approach, aircraft gains altitude and then dives down before it comes back to its configured VS.
For example I’m on left base at 5000 feet descending at VS -800 at a speed of 180 kts; as I extend flaps to final position aircraft will pitch up to a VS +500 and then drops to VS -1200 before it settles down, have to disengage auto pilot and hand fly it as it ruins my final approach.