I just noticed that I no longer can customize a parking spot.
I am sitting at the default KCLT gate C7. There are no .ini files at all for KCLT in C:\Users\Captain\AppData\Roaming\Virtuali\GSX\MSFS
Well, not exactly.
You can't customize a parking spot on an airport that has already an internal custom profile for an FSDT scenery ( in this case KCLT ) that, due to having enabled the SU10 Navdata option, GSX no longer can enable/disable based on the loaded .BGL because...there's no loaded .BGL anymore, only the ICAO matters but, while you could normally fix any .INI profile conflict by simply removing the .INI that doesn't match the scenery, in this case, even with no .INI, an internal profile for KCLT has already loaded by GSX.
We'll need to find a specific solution for this. The only temporary workaround you can use right now, is to remove this file:
Addon Manager\couatl\GSX\airports\kclt_fsdt_MSFS.pye
Remove all .INI you have for KCLT in %APPDATA% and Restart Couatl, should work normally. Note that file will come back when running the FSDT updater.