Lighting problem - What causes this?

I have a small problem with a dodgeball map I’m making, there’s an area of it that won’t light the walls properly. Here’s an image of the problem (it’s a very large image):

Has anyone seen this before?
How can it be fixed?

I can’t exactly see what you mean. Can you clarify?

There is a curved wall with multiple faces, some faces light properly, others don’t light at all and appear solid black.

Dont use model textures.

It may also be an invalid solid.

I don’t think it’s a model texture.
And it’s a valid solid.

you have a leak.
most likelelely

No I don’t, trust me.

Compile log?

Wireframe picture of that area in hammer please.

Fixed it, I still don’t know what caused it.
I just redid the entire area.