Why colors in static mesh editor appear different in level viewport?

Hello, we’ve been struggling for several hours and we can’t figure out why the color, reflections and overall material looks different in the static mesh editor in comparison with the viewport. We know that lights used in both of them are different, that we are using post process volume that might change colors a bit. But it seems that the material is not behaving in the same way either.

Any ideas?
Thank you!