Instead, you should to the opposite and update GSX, and indicate the precise, exact, sequence of all the operations you did in GSX and, since the Fs Labs A320 controls GSX, even what you did in the A320, otherwise we'll never find the issue.
Of course, boarding works just fine here but, again, that's the whole reason why asked for the precise, exact, sequence of all the operations you did, because the issue is happening only when using GSX in a certain way, a certain order or a certain airplane.
Please, don't reply with "it worked before". I BELIEVE it worked before but, how do you supposed we would find a new problem, if you don't do a report as asked ?
So, please, install the very latest GSX update, try again, and report back with the info we need to figure it out what the problem might be.