It's not something we can do much about it, because it's some kind of simulated reaction of the plane when guided externally, which doesn't happen on a default plane, because it's has been added by PMDG. GSX has a documented way for developers to know exactly when GSX is pushing, and it even support a simulation for a Bypass pin, which airplane developers can also use, to turn off whatever internal simulation they have of the rudder/nosewheel system, like a real Bypass pin would do.
We are already been in contact with PMDG about this, and we provided all the explanations so they could update their code to recognize the GSX Pushback.
