Light does not light up brush.
This is how it looks.
They're normal brush textures. Not vertex. In fact the lights are actually lighting up about half of each brush, but not the other half. Nothing could be creating that shadow.
They're normal lights too.
Any suggestions?
Make the light stronger, and use a point_spotlight and light_spot.
I think he means that the lights are 255 255 255 200. That should be strong enough.
Just hide some objects to find out which thing makes the problem.
Or just recreate the room, when you should discover what is wrong. (temporary vmf)
Yea. Oh hey, i'd created the problem myself. I was having too many light styles on a brush.
You learn something everyday 
Sorry to create a useless thread...
If you learn something that's not obvious, it's not a useless thread.
I would call a thread useless if someone would use PTI and wouldnt know how to turn Coop On, ^^