Light affecting entire nearby objects but not farther objects

This is happening all over my scene and I can't figure out why. The red light is casting a red hue, and it's coloring the entire nearby floor tile and not the floor tiles next to that one at all. You can also see the one crate next to it that is lit red while the others are not lit at all. Any ideas what is happening? Unity 2018.4 with standard 3D lighting pipeline, no post effects, realtime lighting.

 

OK this has something to do with the number of lights in my scene. Maybe more lights are hitting my object than the object is allowed to support. When I turn off lights in other rooms this problem goes away. But this room only has 4 lights. Am I not occluding lights from other rooms properly?

 

Problem goes away when I uncheck "postprocessing" in a nearby light's culling mask. Hm.