I have the same problem when resuming a saved flight and I do not use FSBuild. I let FSX generate a flight plan, then manually recreate the flight plan in the PMDG FMC. I've tried saving the flight using the FSX save from the menu, and PMDG save from in the FMC. Either way, the cockpit is cold&dark on resume and no 17sec initialization like usually occures when PMDG starts up.
It works fine resuming one of the tuturial #2 saved flights. But for the life of me I can't figure out how to resume my own saves.
Brett