Operating system: Win 10 latest
Graphics card: GTX 1060
Broken: 2.80 in general
Worked: seems to be a general issue
Short description of error
Shading of meshes will get "flat shaded shadow borders". This effect is called "Terminator Effect".
Exact steps for others to reproduce the error
Just setup a scene with a standard sphere. Smooth it and use a lighting with harder shadows.
This is the effect with HDRI lighting:
This is the effect with an Area Light:
Scaling the Area Light from 1m to 0,3m: