Hey,
With some guys we recently discovered that the rudder in the saber get stuck while you're on the taxi.
Before and when the engine is started you have 100% control of your rudder, but when you push a little bit the rudder get immediatly stuck on the left, without any control of it, you need push more, to gain control of it but not 100% control only a few, that made the saber out of control
but if you succes to takeoff there's no problem in the air the rudder is totally functionnal i tried to check my control if the problem only came to me but it seems to be bugued