Window maximized by aero-snapping, dragged from one screen to another, when restored, returns to the screen where drag started.

When you take a window by the title bar and drag it to another monitor and aero-snap to the top to maximize it, the normal geometry of the window does not get updated. It is still on the previous screen, so when you press restore, the window returns to the other screen.
The normal geometry changes only if the window is placed on another screen in normal mode.

This problem can be easily reproduced with a simple program:

#include <QApplication>
#include <QMainWindow>

int main(int argc, char** argv)
{
  QApplication app(argc, argv);
  QMainWindow qMainWin;
  qMainWin.show();
  return app.exec();
}