This seemed to happen after I started using MSFS AddonsLinker but it appears everything related to GSX is in the Community folder.
You should never use the Addon Linker to enable/disable GSX, because that is only a generic tool that works only for add-ons like airports or airplanes that are entirely self-contained as a package, GSX Pro is not.
That's why, you should always Unlink/Relink it using its own installer, which does all the extra steps the Addon Linker cannot possibly know, like enabling/disabling the right .exe in the EXE.XML, reconfiguring the jetway exclusions for new sceneries that might have been installed while GSX Pro was disabled, reconfiguring the package layouts when the jetway exclusion changes.
To fix it:
- REMOVE all GSX packages from the Community folder, to be sure their links hasn't been recreated wrongly and they *are* Symbolic Links and not real folders.
- Enter the FSDT Installer, which will now show "Relink", and click RELINK, so it will turn into "Installed" (in green) after a few seconds.
- Run an update CHECK to be sure you have the latest version installed.