So basically what happens is the models that aren't covered with some brush turns black. If i walk up to it and shoot it the muzzle flash lights the model(s) up for a second. However, when I do put a brush above it (of course very high) it works, but it doesn't look good. Any known solutions to this problem. Having or not having a light grid volume doesn't make a difference.

are all the models inside the light grid volume? Are the models covered in a full clip texture? Have you tried adding more lights and a few reflection probes?

Yes no and yes

Yes no and yes

make sure they aren't in another surface to far, quick revive looked all black on my map until I moved it out of the ground a little bit, same with some lights I had, they where halfway through the ceiling