We have an accessible hangar in our LPVL scenery, which also has an
environment occluder to block out rain. Starting with SU9, when you enter the
hangar the ground will flicker and stretch, showing its wireframe underneath.
When going to a lower LOD from afar, it looks good. For the ground texture we
use aprons -no use projected meshes or custom textures in the building model.
Therefore, I think the problem comes from the environment occluder which could
be behaving differently. When far it seems fine, but when you’re inside the
hangar you get flickering. I also get the same problem on any building that
has an environment occluder. It seems to be clipping through the Aprons. Edit:
The problem isn’t present when in the scenery editor.
Make sure that the envOccluder Is a Little bit over the ground (any
envOccluder protruding into the ground creates a “black hole”)
Odd, that wasn’t a problem before. I’ll do that.
This continues being a bug in FS24
With the env occluder you are literally asking the game to remove environment
Therefore, if it is protruding into terrain, it will remove terrain (but only when the aircraft is close in my experience)
Simply keep it above terrain and you will be fine 
Maybe hide the base of the env occ in a 3d floor