If you are sure the GSX replacement jetway file for that airport is in the Disable list (and it's not in the Enabled list either), you can be sure the issue is not caused by GSX, and it's just an issue with the scenery not properly excluding default jetways.
Note that, if the problem was GSX jetway replacement not excluded, you would have seen GSX jetways there (much better looking with logos), not default jetways.