Or maybe the problem actually is solved now, and the change of contour is just normal FSX LOD - as mesh-man commented.
Meshman, I zoomed out to the borders of the bizzare land-mass. I'm not sure why you think i should apologize for getting help with an issue that appears at FSDT airports. From the very start, I stated that i thought this was a compatibility issue.
I will do some test later to see if everything is back to normal, at a more useful POV.