well, MSFS has this weird little habit of changing things on their own without you knowing. Sometimes it’s good to double and triple check your settings regularly.
What I also meant was that to reset graphics settings, apply them. then changing the settings back again. At least it may “bait” the sim to use a different texture setting.
Even if you have no mods on airports. It’s probably a good idea to test this using no mods at all, who knows maybe one of these non-airport mods are actually the cause of the missing textures. And does it happen on one airports? Have you tried it on other airports at other places around the world?
Those look like handcrafted airports though. Try with Bing data and Photogrammetry off, see if that helps.