Watching the video and reading your comment I have a theory, it could be completely incorrect but worth testing.
The map compass may be linked to your bodies position as opposed to where you are looking, if this is the case looking through the compass while standing might change the orientation of the character model itself as it turns to line up the target in question, making the map compass direction reflect that. In addition, the orientation of the map compass while seated in a vehicle would reflect the orientation of the vehicle itself as opposed to where the character is looking, given that the seated character model remains facing in the same direction regardless of where the player looks.

When you're in the car, the map compass shows the direction you were facing moments before you got in the car.
I've given feedback before.
T183143