When you see two parking dots very close to each other, assuming this is not really a scenery error, it's possible you are seeing data from the GSX jetway replacement file for that airport, which is only supposed to be used on default airports and MUST be disabled if you have an add-on airport for the same airport.
The FSDT Installer will automatically Disable all 3rd party airports it finds in these cases:
- When you first install GSX.
- When you run an Update check for GSX.
- When you Relink GSX after having it Unlinked.
This means, each time you install a new 3rd party scenery that has jetways, you MUST Disable the GSX jetway replacement file for it, which can be done by either updating GSX, or manually, by clicking the "Disable 3rd party" button in the Config Panel of the FSDT Installer for GSX.
Since you said the scenery has been bought on the Marketplace, it will be automatically detected by the Exclude 3rd party button, because its name matches the official Marketplace standard ( it wouldn't have been approved if it didn't ) but in case of other 3rd party airports, usually freeware, that don't match, you can always add them by ICAO manually, by typing their code to be added to the Disabled list.
This is of course fully explained in the Manual, the chapter named "Jetway Replacements and 3rd party airports at Page 7.