It's entirely normal GSX would replace jetways at default airports even in Trial. They just won't move without a Level 2 license.
Yes, I said "default airport", even if I understood you use Taxi2Gate KMCO, but that answers the 2nd part of the problem, fact they seems to appear in "random" location. They are not random, of course.
The problem is caused by a conflicting AFCAD, most likely one that comes with an AI traffic product, that is taking precedence over the Taxi2Gate one, so GSX reads that file, see it's a "default" ( = with default jetways ), correctly replaces the default jetways with static models, and correctly placed them in the "random" locations, which are not random, but are the ones in that conflicting AFCAD.
The GSX scenery customization page will tell you the name of the AFCAD in use, so you might get a clue on what is causing the conflict.
