It seems that Flap handle Index got broken at or around SU5 ?
If you INC flaps, the Index reaches a MAX value and stays there , even after more INCs (Correctly)
If you DEC Flaps, and the Index reaches ZERO, and then do further DECs, then when you do an INC, while the actual flaps go from Zero to Position 1, the Flaps-Handle_Index, that was at Zero, STAYS at Zero, until the next INC, so is then One Index too low.
This is very obvious if you display Flaps_Handle_Index when controlling the flaps.
Ref above. After 2nd MIN, an additional DEC was done, and thereafter with Ins, the Flap_Handle_Index (blue), lagged the Flaps handle Percent (Green) , by one INC step.
On reaching Max Index, it was re-synced, on the way down.