Strange. As a test, you can try to deactivate Scandinavia East mesh (and Augustin Winther 10M MESH). Use only Scandinavia West mesh (19m) made by Taburet (Scandi_2).
Do you get the same error then?
To deactivate the folder "scandi_1" (Scandinavia East mesh) - insert 2 underscores in front of the folder name:
__scandi_1
Thanks again Hartman,
I tried your suggestion and unfortunately I get the same result as before.
This also happens for me with either mesh (10 or 19m). Looking to it further it seems that in this particular area of Norway an area around the aircraft only is loaded with the mesh and terrain mesh detail further out to the front, sides displays as a flat area then further still you see the high cliffs where after the correct mesh is displayed.
This is most odd and unfortunately an absolute emersion killer, what a shame, especially when it occurs where your fantastic scenery work is displayed 
Edit: Further investigation tonight, it seems to be related to the 60 degree north latitude. It happens around this latitude, then a bit further north the issue seems to mostly disappear (or at least decline) to the point that it's not so obvious.