This used to happen occasionally and I seem to recall I knew a fix once upon a time, but it happens every flight now and I can't find the fix, if indeed I had one...

 

The aircraft symbol is FSNav always follows the flight path off to one side (usually right I think) by a couple of miles, whereas the path on the cockpit flight instruments is exact. Why the difference and can I get FSNav to 'close the gap' somehow?

Magnetic variation?  Just a guess?  I used to have FSNav but that was many, many years ago and I never used it to follow my flight path.

 

Dijvid