Disappearing objects, especially on arrival, it's a very well-known problem in MSFS, which is caused because during the flight, the maximum number of objects in the sim (currently documented at 1000) has been reached, which causes objects start to disappear, possibly causing the whole airport to disappear at landing.
This is usually caused by too high AI settings, but not only. But if it happens in flight (when GSX is not adding any objects), it's the most probable cause, so you should try to reduce AI settings first.
Of course, as soon these AI traffic products came out, and the problem became apparent, we did our part, providing several tools and explanations how you can work on GSX to reduce ITS OWN contribution to the Simobjects number, which are as follows:
- The "Passenger Density" slider will have an effect on how many passengers you'll see at once. Lowering this will reduce the number of objects in the scene.
- The "Extra Ground Clutter" option in the GSX Config panel in the installer, if disabled, will install a reduced version of the GSX Jetway replacement files, which includes only jetways and nothing else, so it won't increase the number of objects compared to the default scenery. This option would benefit ONLY default sceneries, which are the only ones you are supposed to use GSX Jetway replacement files with.
- In the GSX airport customization page, in the "Details" button, there's an option to prevent creation of the static GSX VGDS objects, which are the inactive VGDSs. If used, GSX will only create the VGDS model for the single gate you activated in GSX, so it will save on the maximum number of objects. It's by-airport, since it's mostly effective with airports with many VGDSs.
These are the options you have in GSX to keep the number of objects under control. Of course, the best results would be if you also use the AI Traffic product own options to do the same, since each product can contribute to reaching the limit.