I've had no problems when on a desktop with both monitors plugged into similar interfaces. When you've got one on VGA and one on DisplayPort, or a local laptop

I've had no problems when on a desktop with both monitors plugged into similar interfaces. When you've got one on VGA and one on DisplayPort, or a local laptop display and a VGA on a dock and a DisplayPort also on the dock...it gets confused. Use seems to have largely corrected the VGA monitor + laptop combination, that usually works OK, but digital/daisy-chained combinations with laptops and docks are definitely buggy.