I made a house with three rooms in blender and exported it to Godot, the ceiling is just a plane mesh. So, in Godot, I added a light in the corridor and it looks like It "invades" the other rooms by the ceiling... Like if It was a gap between the walls and the ceiling, but I checked that, and everything is okay and there is no gap between those two.
I tried to replace the plane of the ceiling by a squached cube and re export It... Same. Tried to remake the ceiling inside Godot Engine, same issue.
So what I did wrong? I'm pretty sure that ceiling has a collision shape too, so why the corridor light keeps "flooding" other rooms?

Here's some real examples of what is happening:

inside a room

the further room

the bathroom with the lights off

and the light of the corridor

I probably don't know the correct solution, but have you tried having the wall geometry expand INTO the floor, ceiling, etc?

Also, can you say a little bit more about your lighting setup?

    award OK, but what do you mean with "expand into the floor and the ceiling"?

    here's the settings on the corridor light:

        BlackSaturn OK, but what do you mean with "expand into the floor and the ceiling"?

        I mean the geometry of the quads/planes used for the walls. Do they extend through the ceiling or only to the ceiling? Extending through the ceiling could potentially block the light leaking through, but that's only a hypothesis.

            Regarding the reflections on the floor/ceiling, that looks like a specular map issue to me. Maybe cubemaps will help. In addition, if the ceiling/floors are one big mesh, try breaking it up so each individual room has their own.

              6 days later

              Megalomaniak I have enabled it for some time but when I noticed the fps getting lower I disabled it, but it doesnt change anything about the lights

                  3Dsander I don't really know what are cubemaps, but i'm gonna try my best to find info on the internet on how to use it properly...

                    award you mean like clip them inside each other? (sry if i'm being stupid lol)
                    I tried to lower the ceiling until it goest through the walls, but it keeps flooding the lights

                      BlackSaturn I have enabled it for some time but when I noticed the fps getting lower I disabled it, but it doesnt change anything about the lights

                      You mean you enabled and then disabled the shadows?