I can also confirm this bug, except it is not only the Spitfire that this is happening with. I also get this with the yak-52, and the bf109 (all other aircraft were tested and did not have this bug)
Anyways these are my notes:
Holding rudder left key and letting it reach max yaw left, then releasing it results in the rudder (and cockpit pedals) moving and sticking to the right (they never release on their own). Same for the other direction.
While locked rudder left, I press right rudder and release the rudder will move and lock left. If i press left rudder while it is locked left it will release the the rudder to center.
This only happens if the rudder hits the end of its travel, if it doesn't hit the limit it returns to center.
If I try to fight the rudder moving to the opposite direction. It will stop moving while I hold the opposite key, and continue moving in the same direction once i release, and it locks as normal
Looking at the input panel, it shows the input for me pressing yaw right, and when i release the input moves and locks left
I have no joysticks or controllers attached, all pilot aids and assists are turned off including the plane specific ones. I also verified files, and deleted my entire profile
This issue only effects prop planes, and has been tested on all the other prop planes, the other planes the rudder instantly snaps to center when the keyboard is released
This issue happens in both the ground and air using the z and x keys