Since the glitch only seems to happen at airports in southern Arizona, I wonder if it might be a terrain mesh file or perhaps a texture file that covers that part of the state.
My first thought is a bad file in a scenery folder, but half of a big state seems like a lot of area to be affected by an airport scenery.
Have you done the troubleshooting step of inactivating or (temporarily) removing the most recent things you've installed, one by one, to see if that might reveal where the bug is coming from?
I feel like it has to be a bad file of some kind, either newly installed or an older one that somehow got corrupted.
I wish I could offer more than guesswork.