Operating system: Windows 10 Home
Graphics card: nVidia GTX 1050
Blender 2.8 Beta date: 2019-01-19 20:58
Downloaded from the daily build page on blender.org.
Short description of error
I've got a buggy file in which EEVEE diffuse shaders always act as if the world is the default material,regardless of what I set it to. If you open the file and render, you'll see that the world material is black, but the darkest shadows are still middle grey.
Exact steps for others to reproduce the error
Not sure, it happened while I was creating some complex toon shaders in EEVEE, with dozens or hundreds of nodes. Could have happened at any point.