This has been a bug since the very beginning. If you want to make a part with multiple colors, they don’t match any of the normal parts with the same color and material.
I think just unioning a part with itself is enough to change it
I also noticed this a long time ago. The difference is slight but noticeable. I think the explanation is that even regular parts have slightly varying colors, but for some reason CSG parts deviate even further from the base color than normal parts do. I’m not sure why this is, though.
The only examples I know for sure I have are from back in August. Does it still do this with new unions?
I think it just has to do with how the CSG engine picks vertices for the geometry.
