Why is light complexity brown?

light complexity in my scene shows up brown instead of according to the settings in engine.ini or baseengine.ini.

Why is this?

See the documentation page here

I have the very same question, even when i only have 1 single light, the complexity always appear brown (like 4 lights affecting) i cant find an answer either.

You’ve probably imported the mesh as a static mesh, or set the blueprint the mesh is in as movable. These objects do not get calculated in the light bake because they could move. Only static meshes will be computed in the lighting build.