I have this problem as well. I fly the Citation almost exclusively and even when parked if I hard right or left the rudder, I can see it jumping about. Even if I hold the rudder all the way to one side or the other, it will jump back to center intermittently. I’ve always had a hard time turning the aircraft on the ground, unless I was rolling at a sweet-spot speed… then it handled great, but at slower speeds I’d rather be steering a sheet of plywood with a rope.
I’ve also noticed that the reverse thrust works fine if I start a flight from a runway, but if I try a cold start I can never get the reverse thrust to back the aircraft up from a gate. I must be missing something.
I fly the stock MSFS Citation with no third party addons.
Jim-Sim
[Edit: Problem solved. I had my HOTAS that I use for Helicopter flight still plugged in… once I pulled the USB out of that… everything is fine. I remember setting rudder axis to the twist of the stick… and so did MSFS. ]