My very simple metal material has a black area and I don't understand why 😭

I have a very basic metal material and it has this weird black area on it.

This is what the material looks like:

It appears that there’s always a black shadow at the bottom of the example orb (due to lighting) and setting Roughness to a low value results in this distortion that pulls it upwards. This black area also appears in game, making the mesh almost completely black.

I tried with just one basic colour and it makes no difference. The only thing that seems to make a difference is increasing Roughness, which returns the black shadow to the bottom of the mesh.

This is meant to be a reflective chrome-like material and I don’t want to increase Roughness. :cry:

What is it I’m not understanding about this material?

Does this happen outside of the material editor Preview?

Yes:

This black area also appears in game, making the mesh almost completely black.

It’s even worse because the black area is right in the middle of the view from the camera. :cry: