The level became dark at some moment

Someday my level became dark. I don’t remember when it happens because there are well-lighted levels (not like this).
There’re no atmospheric fog, no directional lights, and no skylight. It’s kind of a building. But I bet you it was lighted even in complete darkness.

And Look at the scene before:

There is a crucial difference. Objects in the complete darkness are highlighted with blue color. It’s okay. But now it looks wrong.
I turned off Auto Exposure for the project. (It doesn’t work if it’s enabled)

Why would it be lit if there’s no lights in it? It looks like there’s a spotlight in the one area, yet the other picture with the blue hue is completely lit even though it’s a dark lighting. What are you trying to do without directional or skylight in the level?