The light from the spotlight shines through.

@CloakPin I tried it and it didn't work.

@CloakPin I made a box out of fuel tanks and the spotlight was supposed to shine there, but the box let the light through.

I remember this happening (spotlights shining through objects) many times in the past but have not noticed it recently. However I also had different settings back then, like shadows were disabled. Not sure if it is shadows or some other setting or just a change in the game but ....

Just tried it.
I have no light passing through any details.
What are you able to make it pass through?

Change its intensity i believe.
I havent played with it in years but you used to have to create two layers of building to stop the light from going through objects