Scenery Problems in eastern Netherlands after WU6

Please tag your post with #pc and/or #xbox.
#pc
Are you on Steam or Microsoft Store version?
store
Do you have any add-ons in your Community folder? If yes, please remove and retest before posting.
no add-ons
Are you using Developer Mode or made changes in it?
no difference whether you are in Developer Mode or not
Brief description of the issue:
Scenery displays dark tiles around the aircraft when flying low over the eastern Netherlands. When flying westward, effect stops at a seam cutting N-S a bit to the west of Leeuwarden
Provide Screenshot(s)/video(s) of the issue encountered:



seam_north.PNG

Detail steps to reproduce the issue encountered:
no special steps necessary, just fly there
PC specs for those who want to assist (if not entered in your profile)

Build Version # when you first started experiencing this issue:
after WU 6
Are you on the Steam or Microsoft Store version?
store
Did you submit this to Zendesk? If so, what is your ticket #?
no