The only change to my flightsim setup was the update to GSX and I don't use an AI traffic pack. So the GSX update has done something to override the addon scenery.
But since GSX doesn't do anything like that, especially not the Update, the only possible explanation is something else changed the Scenery Library without you realizing it and the GSX update just happened to be coincidental.
There's only ONE scenery area that comes from GSX that is added to the simulator Scenery Library, and it's the Addon Manager\Fsdreamteam\Exclude folder.
This contains the Jetway Exclusions .BGL files you create when customizing a 3rd party scenery to exclude its standard Jetways to be later replaced by GSX ones and, in order to trigger a CHANGE in this area, you need to do as follows:
- Start customizing a 3rd party scenery
- Enable the Jetway Exclude checkmark for some parking spots
- Exit from the Sim
- Start the GSX Control Panel
- Let it Compile the newly created XML file for that airport, which will create a new .BGL in the Addon Manager\Fsdreamteam\Exclude folder, which will contain only Exclusions rectangles for those parking spots you said you wanted to Exclude
This is the ONLY place in GSX where a change in the Scenery Library could possibly happen. But, since you said it happened after the Update, it surely cannot be the case, since the Updater will never touch or change anything in that folder, whatever you already had in it before, it was there even before the Update.