I have tried loading several of the default aircraft that comes with X-plane and have the same problem. I start them all cold and dark and have noticed that the CRS knob is spinning even with battery and avionics switches off.
I had this issue with 10.45 although not at first but also did not notice when or what things were going on as to when the spinning crs knob started spinning. The heading adjustment like I said jumps about 30 degrees when I try to adjust but when trying out other planes it seemed to work ok. I have updated to 10.50 with the same problem and just recently updated to 10.51, released a few days ago.
I might add that I have the same problem with the few free aircraft from x-plane.org site that I have tried. I just this morning bought Carenado 500S_Aero-Commander and when I loaded it direct from the start x-plane crashed. I then restarted x-plane with a different aircraft and when it was loaded switched to the new plane. Same problem with the crs knob and pointer spinning.