Operating system: Windows 8.1
Graphics card: NVIDIA 740 M
Broken: (example: 2.80, edbf15d3c044, master, 2018-11-28, as found on the splash screen)
Blender 2.80 released candidate
Short description of error
The interior edge of the cube has a strange lighting edge of the cube only the face where the light intersects it.
See my test blender file:
See my screenshot:
I tested with all lights
A good approach to reality is on Spot Shape - Size is < 41.6
Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
create a scene with volumetric light