When I first installed V1.9.9 of GSX I, like others, had some random vehicles missing, not always, but regularly. This appeared to be fixed in a later update. However, over the weekend the problem has reappeared.
In order to try and remedy the problem I have uninstalled GSX and the paintkit. I have downloaded the full installer and the Vehicle update and installed them both. I have used the default airport LFPO (Gate G13) and I still get random vehicles missing. Sometimes it is a complete baggage train, sometimes an individual cart, sometimes the tractor. I also have the belt loader and stairs missing. I attach images of some of these. My sim is FSX Acceleration.
I also attach a copy of the Couatl.log that shows the following error repeatedly. This log was taken from the third occurrence pictured (i.e. the one with the missing rear loader and front baggage tractor).
Requested assistance services at Gate G 13
Error: exception UNRECOGNIZED_ID in call SetDataOnSimObject param #2 '78909184'
{'Airport': 'LFPO', 'Requested assistance services at': 'Gate G 13', 'User Pos': (48.72557779308308, 2.358349991957877, 92.0438 m, 3.34781 m, 340.7999948663637)}
There is another thread running similar to this, but I have opened a new one as in that case there seemed to be a focus on UT2. In my case, I have some AI provided mostly by Traffic 360. I do not have any addon weather running when these problems occur, nor any other external program such as FS Passengers. The plane is the iFly Boeing 737-800.
I hope you can help in diagnosing the problem.