The problem is that the baggage carts start to move away from the aircraft when the boarding starts. They move to some remote parking space and then at some point turn back to the aircraft.
First, they are not the same loaders.
As soon as they go away, different full loaders have already started coming from a terminal, and this is obviously more realistic than having the empty loaders auto-magically pop-up around the airplane and magically become full, just because you decided to start boarding, instead of deboarding. We cannot possibly know if you are starting with Boarding. If you start with Boarding, they can be empty and go directly from your airplane, but if you start with Boarding, they must come from somewhere else, full of bags, and it would look silly if they materialize in front of you already full.
But I think GSX should cater for situations like this with a reasonable solution (rather than the user having to fiddle with addon airports afcads). Such addon airports are not rare exceptions.
Long ago, GSX had a limit over where to search from a suitable place to have the full loaders to appear. It searched for parkings not in front of you, but not so far that would require waiting too long. However, following many user reports of faulty AFCAD with not just A SINGLE vehicle parking spot, we had to increase the search range, up to the whole airport, otherwise could find any place to start from. No, we cannot just place them anywhere, because the starting point *must* be part of the AFCAD layout, otherwise nothing can guaranteed the vehicles won't end up walking over grass, which is what would happen if we, for example, decided to place them, let's say, 500 meters at most away from the airplane if there's no better parking.