Intel Core i7, 16 Gb RAM, NVidia GeForce RTX 2070
Windows 10 x64
Short description of error
As far as I can see, something was changed in Blender Bump and it looks like that change introduced numerous problems:
- Lights behave very strangely and look wrong. Notice the wrong hightlight and lack of shading on the left side of the plane.
- Mixing shader nodes became problematic - in some cases mixed material becomes significantly darker and sometimes Bump stops working on large Height values.
- Overly darkened Ambient Occlusion where objects with Bump visually or physically overlap each other.
- Contact Shadows doesn't seem to work in some cases.
And several other assorted problems.
Exact steps for others to reproduce the error
Take a look at my render or open provided test file and set it to Rendered view.