[brazen1]

It appears stereoscopic 3D is turned off globally when any file is played using madVR. Under 'Rendering/stereo 3D setting' no amount of fiddling with the 4 adjustment works properly. It either results in playing back the title but never turning stereoscopic back on at system level or crashing the player before playback even begins. Turning off stereoscopic at system level, madVR will perform proper no matter what settings are selected.

For now I've left it at:
Enable 3D
When playing 2D -Checked - Disable at O/S level
When playing 3D - Unchecked
Restore O/S 3D settings when closed - Checked (This doesn't work. Have to manually enable every single time for 3D playback)

For now I guess I could add
C:\Program Files (x86)\NVIDIA Corporation\3D Vision\nvstlink.exe" /enable
to my .bat for 3D playback in order to restore the setting when it's really needed.

It's always something. It's a shame. I was looking forward to employing this as a daily driver because HDR with 3DLUT looks very sharp compared to others imo but if it breaks other perfectly working formats I'll have to weigh the pros and cons. Hopefully someone else has experienced this and will provide their solution. Perhaps it's already a known bug and there is no solution especially with 3D pushed out of the big picture. Maybe I've got a conflicting adjustment somewhere although I've been chasing this for hours now. I give up.