(recent preview release Enscape-Setup-2.4.2.2124-gd384852 & SU18)
I am finding that when I am close to metal objects, unless they are 100% lightness, they show as black. (While moving or changing the DOF they show the correct brightness, then when it starts 'cleaning up' and sharpening it overlays a black shiny surface... it renders the same way.)
If I pull back a little bit it renders properly.