As explained many times already (too many times to count, really, there's even a blue highlight on the manual), GSX doesn't control, doesn't affect, doesn't change, is not affected by, anything related to jetways.
They continue to work (or not) as they always did. Installing GSX won't change anything about how jetways operate. The only form of interaction, is that GSX can detect if a native FSX jetway is present on a given parking, by looking at the scenery AFCAD, or it can customized by you, to indicate which parking spots have jetways, if you use a scenery with static jetways which can't be detected automatically.
This is done ONLY to prevent the generation of front stairs and the passenger bus, nothing more. There are no other interactions between GSX and jetways and, GSX can't possibly know, automatically, if on a specific parking the central position will be correct in order to have the animation started, because this changes depending on parking radius, jetway origin position in the parking, proximity of other jetways nearby and radius of the nearby parkings AND the airplane reference point and the location of the Exits in the airplane.cfg.
Is not really possible to anticipate IF that jetway will work, without trying.
BUT, in future releases, we are planning an update that will allow users to freely place docking systems or marshalers AND define the exact parking position so, at least, you might be able to customize it if a parking has a problem when the airplane is parked in the default position (the center of the airplane in the center of the parking)
