Light Values changing after re-starting and loading project file

I am lighting a space with a specific light intensity.
The light is illuminating the room, as it should and I can see the final result in my viewport.

I close the Unreal Engine Project.
Load the file again. The lights do have the same light intensity value, but the result in the editor is much dimmer. Much darker. It’s not just barely visible, it’s like day and night.

If I change the light intensity value, and re-enter, the light is back to normal.

It’s a huge problem, when you have hundreds of lights on a level.

Does anybody experience the same issues?
And how to fix that?

thanks for any little help, appreciate it!