Edge 1040 "snapping" my courses to internal map

While navigating courses on my 1040, it keeps adjusting my gpx courses to fit its own view of the world. This is super confusing, especially since often the on-board maps are not up-to-date with latest trails. It's gotten me totally lost several times, and is also confusing.

I looked closer today and it seems it keeps both on the screen, but the one with the arrows ISN'T my course. The one with the arrows is what it thinks in the course (and is wrong).

Does anyone know how to disable this? The gpx tracks I'm following are usually much more accurate than the map data, especially for mountain bike trails (which is where the problem is the worst for me).