Rendering - Metallic Issue

hello guys

I’m having an issue in metal objects, when the roughness values tend to white.

If you check the image UnrealResults, well see the problem, there are some spheres that turn to full black (the first two rows are metal = 0 and the last two row has metal = 1), and there is a rough texture that vary the roughness value.

Is that normal this behavior?. I’m using Skylight. In other image I show you the result in Painter, that it’s actually what I expecting.

But, in the other image I added a Point light and the Metal spheres respond correctly.

So why with the Skylight some spheres are black, depending of roughness value?.

Unreal 4.22.3