This thread is interesting and was also discussed here :
Service vehicles using ATC network assigned to aircraft! - Airports & Sceneries - MSFS DevSupport
It is a problem going on almost since that AIVehicles appeared in FS…Each airport/airfield should comply with the fact that AIVs and AIs networks should be fully and totally independent.
The only solution would be that, through the SDK, MSFS introduces a rule that Taxiway must not be use in no circumstances by AIVs. But…
TaxiwayPath Objects
Here, the most important sentence is :
“Vehicle - This path type is specifically for airport support vehicles, and aircraft won’t use them. Vehicles will use them if they are available and link correctly, but note that vehicles will also use other path types if a vehicle path is not available. If you have assigned any markings to this path type, they will be different to the rest of the types, showing that the path is purely for vehicles”. The important word is “also”…
AIVs have their own taxiway supposed to be…TaxiVehicle, but, as it is indicated in the SDK, if AIVs do not have their own taxiway or if they feel uncomfy with their owns, then they will grab the first single link available they need to go here and there. Please note that AIVs are programmed to serve all gates/parking available in the Scene and there’s nothing to do about that except to put the slide to…zero for MS2020) or OFF for 2024.
Hope it helps.