This happens so many times, especially around car fenders that are supposed to be smooth… It’s also a bug related to the “Extract render mesh” command. It destroys the smooth shading of certain polysurfaces.
Years ago I proposed to implement an approach similar to “Smoothing groups” in 3ds Max (the ability to assign individual shading properties to select polygons), but still nothing…
Edit: Here is the bug in action.
The older I get the more I understand this
Here is another one I got from mentors during jobs:
“Hide your power levels”
“Work slow so that we have more work for the week”
“put the feed rate at 50% the machine won’t crash easily and overflow with machined parts”
Some of these are not good advice 
When you are struggling coding mesh scripts with Rhino and Grasshopper preview transparency make you go “woah”
metallography plugin incoming ? haha
Cat Pareidolia 
