Not UAC settings, a UAC prompt raised by an app requiring Elevation - Task bar shortcut that points to D:\Temp\Shared-MMC\Domain-Forest.msc.
Regardless of user, this msc raises a UAC prompt, however only when I invoke this for another user is it a problem, the UAC prompt never appears, normally the screen freezes and the UAC prompt is in foreground, I am suspecting that the prompt may be hidden.
Sorry @Tihiy upon further testing this occurs without SAB as well; I guess this version of W11 is hosed. Did an IPU which seems to have fixed things.