I noticed a similar "problem" with my Foka 4 edited in RC8 and copied into RC9 "aircraft mod".
In the air sometimes the left airbrake seems to follow in the air behind the left wing about 1/2 meter like a ghost.
And after a bumpy landing far down the hill both airbrakes look to be extended despite not activated with the transmitter.
Until now no such phantom with the original.
Kind regards from Switzerland