Switching to VR splits screen into two smaller (mirrored) screens, but no image goes to the headset (just sound)

[sehnsedahamses]

Try this:

WMR Portal
Settings (bottom left)
Headsetanzeige (in german, left 3rd under Mixed Reality)
Optionen für das Benutzererlebnis (again in german, maybe “options for user experience”…)
klick on change there, then try to set refresh rate from automatik to something else, here 60Hz and 90Hz where posible).

That solved this issue here. Good luck.