Are you sure about KORD ? Because all the others require the latest GSX installed, since they use GSX L2 to create jetways. But KORD uses standard jetways and we never made a GSX configuration for it so, unless you made (or downloaded) one that requires GSX and haven't installed GSX, it's not possible that jetways in KORD would just disappear.
Or, more precisely, jetways in KORD could only disappear because of ANOTHER scenery in conflict.
The others, as I've said, require GSX L2 to be working. Of course, it's free to use there so, fact you bought it or not, is not an issue.