Lighting works fine on -medium but comes out awful on the final pass....

Just as the topic says, the lighting on one particular wall comes out like this when I run a final pass:
   

But it renders just fine when doing a test build (light -medium). It was even working before just fine so I'm honestly at a loss for what might have caused this / what I should try changing.

Any idea what might be up here?

I have seen this a lot of times with patches and models: 100% black surfaces
and/or random black splotches.


I know some different ways to try to solve this problem:

 1- Compile the map using reflected (bounced) light.

 2- Use a different lightmap resolution for the problematic object:

    For a model: "_lightmapscale" "0.5" in entity properties.

    For a patch: exactly as above ("func_group" the patches to have own entity properties).

 3- Rotate the object a few degrees or move it a few game units.

 4- Try this shader directive for the texture:

    q3map_lightmapSampleOffset 8

    This directive is an offset for light sampling that can help a lot to fix
    black splotches in lightmaps.

1: such sort of splotches definitely happens with load of relatively tiny portals on the way of light; solution is to use detail brushes
2: can't it be the effect of grates with alphashadow or lightfiler?
You also may try to remove switches from Final preset one by one to figure out which one is responsible for splotches

1: such sort of splotches definitely happens with load of relatively tiny portals on the way of light; solution is to use detail brushes
2: can't it be the effect of grates with alphashadow or lightfiler?
You also may try to remove switches from Final preset one by one to figure out which one is responsible for splotches

Looks like it's definitely the glass / mesh (removing them makes the problem go away), though switching alpha shadow off doesn't appear to help much.

I'm currently debating whether to figure this out further or take this as my cue to redo the area (I wasn't completely happy with it, so this may be an opportunity to replace the visuals with something else).