This has been going on for a very long time. I don't use much non subd geo, but when I do I get some type of shading error in octane when I render. You can see it in the images. That was just selecting all the edges on the center cube and beveling a little bit with like 4 segements. You can see the reflection is off. So to fix it. I have to select all 6 of the incorrect faces hit the "B" key for polygon bevel and literally drop the tool while it does nothing. Then it corrects the shading. So every time I bevel I have to go to every face afterwards and just hit the B key, not change any settings. Then drop the tool, then it corrects to the proper shading.
Hopefully I explained everything well enough in the pictures!
I must have some setting wrong maybe? Octane 4