In Revit 2020 using the new material type and a PNG file in the roughness channel, there are close-up rendering artifacts when viewed in Enscape 2.6.2.
The textures were generated in Substance Designer and exported to bitmaps. I've tried both 2k and 4k resolutions, but the results are identical. Here's a crop of the full map:
And here's an up-close from Enscape:
I've gotten the same results in three different projects and on two different computers.
The first has a GTX 1080 card, the second has an RTX 2080TI card.