The bug: If you have flaps down, and one is destroyed/shot off, it will act as if it's still there, and will remain at whatever state it was when it was blown off, regardless of speed.
I.E. You're in a ki84 and you are at about 150 with 2 notches of flaps out, and you lose one flap. If you nose down to run the other flap retracts, but the MISSING flap does not, sending you into uncontrolable rotations if you don't fly slow enough to keep the remaining flaps exactly like they were when you lost one.
This bug has been around for many versions. I wonder if HTC is simply trying to find the best way to deal with it.
The suggestion: If you lose a part that retracts and/or affects drag and lift (any gear, flaps, dive flaps, dive brakes) simply have the destroyed item RETRACT and stay there.
From my observations when a flap is shot off it merely is no longer shown. It is still there, locked into place, but it is not displayed. So simply have all parts that are NOT being displayed revert to their default (retracted) positions. It is slightly redundant, but it WOULD fix the problem of the flap bug.