This is destroyed if all the passengers must walk up imaginary steps into and out of the plane
Can I ask you to review all my comments and see if there is any clue to why the stairs frequently fail to turn up with the driver?
I already told you, missing objects are usually a result of using too high AI settings, even more likely with AI Injection, which will cause the maximum number of objects the sim can display to be reached. Nothing we can do about it.
What you can do in GSX to fix this, but it's only valid for default airports where GSX has replaced jetways, is to disable the "ground clutter" option in the GSX Config in the installer, then run an update again, so a more lightweight version of the jetway replacement files will be installed, with only jetways, so it won't increase the number of objects compared to the default scenery.
Other than that, I can't see any other reason why you are missing some objects, unless there's something else OTHER than AI Injection that cause the same problem. The maximum limit of objects in MSFS is a limit, regardless how it's reached, AI injection is just the most common cause, but that's not the only one, I guess on extremely detailed airports with too high settings, it might be reachable just without AI.