Even before it was updated to use GSX/SODE, KLAS never had static jetways, they were always dynamic ( just using the standard system ) and, if you have the default scenery overlapping for some reason with FSDT klax, it would also have default animated jetways.
So, if you see static jetways at KLAS, they must come from some other scenery that is not FSDT and it's not default you must have installed.
Check the GSX scenery customization page, and see the name of the AFCAD in use, it might give you an hint where the conflicting file is located.