GSX never tries to open or close doors on any airplane. And neither the PMDG, as far as I know, has implemented any kind of automation like that ( it's possible, but I don't think PMDG ever used that feature ).
Is possible you installed some kind of 3rd party automation utility, perhaps a script made with LINDA, that is reading GSX status and is trying to automate doors and, for some reason, is not working correctly ?