Why is it that the mixer positions are not saved in the project?
Every time i open a project i have to drag the all the mixers to their dedicated screens (multiple monitor setup)
They are also not saved in workspaces.
I have Nuendo 8.3, Windows 10 with last update, Nvidia gtx760 and have no problem with my three monitors system. All positions of main project window, mixer and video (though it runs not in full screen as I save project) save correctly. I remembered issues similar to yours when I had windows 8.1 on different daws and video editors. So maybe the system brings you problems. And sometimes updating videodriver may help. Also returning back to some specific old driver may help as well.