As explained many times on the forum, whenever you are missing *just* jetways, it's NEVER a problem of the scenery, and it's always a problem caused by something else.
The only thing that can exclude jetways, it's another scenery AFCAD so, check all the following:
- You don't have another scenery in conflict. Use the free FSX Airport Scanner to find it.
- If you use AES, check that is not excluding the jetways, because it also comes with its own AFCADs which are used to exclude jetways in a scenery to replace them with its own so, an issue with AES might also be the cause of disappearing jetways.