Why are heading in PFD and map off by exactly 10 degrees? I was flying on my X-plane 11 flight simulator today and noticed something quite unsettling.

This was a VFR flight between KIAD and KDCA. I pulled up my map for reference and noticed I was flying orthogonal to the map's north direction, even though I was flying a heading of 100.



The image shows the map and the PFD for your reference.

What is going on? Did I mess with some heading calibration setup? 100 degrees and 90 degrees are perfectly 10 degrees off, so I don't think this has to do with magnetic north issues.

P.S. Strangely, I got to my destination simply following the headings from ATC.
KIAD has a magnetic variation of 10 degrees west, and KDCA has a magnetic variation of 11 degrees west, so true vs. magnetic north actually makes sense.