Operating system: Windows 10
Graphics card: Geforece GTX 1060
Broken: 2.80, 84c06e996a7a
When you try to change Roughness of the Transmission in the Principled BSDF node it has no influens on rougness of the refraction. But if you change roughness of the material in change the roughness of the transmission. Is it a expected behavior or a bug, I don't know but it make me think that it's a bug because of independent Roughness for the refraction exist in the node.