GSX Pro is still not reading the correct parking spots, it's still reading the default airport instead of the marketplace airports
Assuming you have the SU10 Navdata API Enabled, you can be sure GSX will read whatever parking spots the simulator is showing.
This includes CONFLICTS because, when the SU10 Navdata is Disabled, and GSX needs to decide by itself which .BGL to read, it might either load the correct .BGL, or the wrong one, but at least it will only read data from ONE single source at a time. Obviously, in case of Marketplace airport, if the Navdata is Disabled, GSX will read data from anywhere *except* the scenery you are interested in, so it will usually read the default.
Instead, when the Navdata is Enabled, GSX will NOT read ANY .BGL: it will just ASK the sim a list of parking/runways/taxiways for the currently loaded ICAO, and this, as I've said, includes conflicts so, if you have data for the same airport coming from multiple sources, so you'll have double parking spots ( they will show on the Map ), GSX will get everything, conflicts included, because it simply renounces to do ANY kind of choice of *where* taking its data from.
One source of conflicts might be the GSX Jetway replacement files, the common cause for this is not having run a GSX update or an "Exclude 3rd party" button AFTER having installed a new airport. Only running a GSX Update OR clicking the "Exclude 3rd party" button OR adding an ICAO manually AND applying the changes will result in the GSX Jetway replacement files being removed for the add-on airports you have.