Inbound Graphic Glitches

Hey Pilots!

On my last Flights occured a graphic glitch where the Runway is covered by Grass Textures or sometimes it is covered and the Runway flickers thru the grass. But this is not visible when I load the Airport initially. I loaded an airport if it looks okay, but when I later fly inbound to this airport the glitch appears.

This happens on freeware scenery and it also accured on Payware Scenery, Oslo Mega Airport for example. I use FTX Global with Vector - but I alredy have disabled it for the Airports where it was glitching with no success.

I have now absolute no clue why this occurs... maybe someone knows this and a solution?

Thank you very much!