After upgrading to 4.11 my lightning looks really dark in this place. The “grating” is a 2 sided masked material on a single plane mesh if that matters. there’s 4 static point lights behind the planes. As soon as i move the lights somewhere it looks like it should, but after light build it turns out like this.
I did get the external reference error too if that matters. I solved it like everyone else > renaming project folder > relaunch > save.