I have had this before. Edge peak uses head tracking for looking around (3D edge peak) and you can set the background to black instead of “ambient”.
In my case sometimes the head track got switched backwards so when I was edge peaking the display would look plain black. BUT if I turned all the way around (180 deg) there it was behind me. Try using the recenter view button when you edge peak.
Hope this helps.
If your display is turning all the way off you may have another problem.