[mclingo]

Most don't need fullscreen exclusive mode for HDR passthrough. If you do, it is probably limited to the Nvidia driver you are using.

I can get both HDR and 3D without FSE but I get frame drops / slkips and black screen of death coming out of movie, I need both FSE in MADVR and windowed mode in DS to get a fully perfect picture.  

I see. Must be an AMD issue. I've heard FSE doesn't work correctly with the newest Windows release. Does this also impact HDR passthrough? 

I have no issues with HDR passthru at all, FSE on or off, just frame skips when off.