Only KIAH looks like this.
That's why I said there's seems to have been a problem with the program recognizing the sim (usually because of the Migration tool), because this is how it's supposed to look like, if the program believes it's running in FSX, so it will modify the scenery accordingly when the sim starts, before creating the objects.
Or, perhaps the patching went wrong, like the antivirus blocked access to the C:\ProgramData\Virtuali folder, which it obviously shouldn't...
You might verify if this is the case, by enabling Logging in the Troubleshooting section of the GSX Settings page and after entering and exiting a session, check the Couatl.LOG file that has been generated. It should say something about having patched KIAH.
Yep, the entry in the log file is as follows:
Entering KIAH area...
Patching for Bloom in P3D V3 in file FSDT_KIAH_sf01.mdl 0
Patching for Bloom in P3D V3 in file FSDT_KIAH_sf02.mdl 0
Patching for Bloom in P3D V3 in file FSDT_KIAH_sf03.mdl 0
Patching for Bloom in P3D V3 in file FSDT_KIAH_sf04.mdl 0
Patching for Bloom in P3D V3 in file FSDT_KIAH_sf05.mdl 0
Patching for Bloom in P3D V3 in file FSDT_KIAH_sf06.mdl 0
Patching for Bloom in P3D V3 in file FSDT_KIAH_sf07.mdl 0
Patching for Bloom in P3D V3 in file FSDT_KIAH_sf09.mdl 0