Is this a problem with GSX or with SODE?
It's a problem of both. As of today, whenever any developer uses SODE to create a jetway, we need to do a small update to GSX, to protect their jetways to disappear, like we did for several sceneries like those from Drzewiecki.
This will not be required anymore in future versions, since we are working right with SODE author to improve the SODE API to be able to know automatically which and where there SODE jetways in a scenery, which is part of the integration with GSX we are doing, but for the time being, we would need to add a specific code to deal with each new scenery that comes out with SODE.
To do that, we would need to know the titles of the jetways used by that scenery. They are probably located somewhere in the Simobjects folder.