Applying that before importing your model means that the faces along that edge are not actually connected and a tiny bit of light will fall through as a result.
Unity point light goes through walls.
You have a point light source behind some walls.
Shadows are the obvious answer however i assume you are using lite and that s not an option.
These options have obvious edge cases that can t be easily resolved.
In blender there is an option called edge split which makes edges sharp.
1 set the range of illumination to just reach the wall the strength of the light on the wall will decrease.
2 increase the intensity as you want and you will see that the light is now illuminating just the wall and don t go through.
Set your torches up with flame particle systems and then set the point light at the center of the hallway between the two torches.
The particle systems draw the eye away from the origin point between them and the majority of players aren t going to notice that detail anyway.
Place it just behind your wall so that it blocks the light from leaking out.
How to fix indirect lights seeping through walls.
I ve had a similar problem with my models.
Here is how to fix it.
In that case you ll need to be a bit more clever.
You can simulate this in shaders or use raycasts to see if the light is behind a wall.
That s why shadows exist.
It s really just a shadow type setting that needs to be set right.