Your screenshot clearly proved this is not a GSX problem, because those jetways are not coming from GSX, they are part of a 3rd party scenery.
Of course, I'm assuming you are using GSX correctly as explained at Page 7 of the GSX manual, which clearly says ( under the "IMPORTANT" heading ) that, if you use a 3rd party scenery, you must Disable GSX jetway replacement files for that airport, because GSX replacement jetways are ONLY meant to be used with default airports, they should not be used on 3rd party airports.