Ok this is a weird one.

[Mr.Mxyzptlk]

I was going to make adjustments to a material so I made a copy in case I needed to revert. This is the same material in slate. I changed nothing, just made a copy. Curious why the new one on the left looks different.

To test I did the same with a few other materials and the copy looks identical. It's just this particular one that has an issue.

[vladimir_krastev]

Hi what happens if you test the same thing in a new scene?

[Mr.Mxyzptlk]

Hi Vladimir,

Still getting the same thing in a new scene.

[vladimir_krastev]

And does it render differently?