I've had about 5 total lockups, though can only remember details of 3:-
1)  Whilst in Ostwind, killed lead Boston III in formation, at same time it dropped bombs and.... lockup.... presumed lockup on death.
2)  In Typhoon, auto-takeoff.... lockup.  No other aircraft sighted in area.
3)  In P40E, came down vertical on airfield, vulched 109, lockup.  2 or 3 enemy aircraft in area.