Ah the usual response, problem is on the customer side, nothing to do with us lol. I should have seen that coming a mile away!
Clearly it wasn't because a) I have had everything GSX related, program, Addon Manager, all folders, GSX executable, updater, airports etc you name it excluded in my anti-virus since the first day I installed it because I remember how finicky coutal was in the P3D days and b) Other then check to make sure everything was still excluded I didn't do anything else or make any changes.
Lo and behold I ran the updater again and this time it completed normally with everything downloaded.