Example of what I mean:
http://img153.imageshack.us/i/screenshot8ch.jpg/
http://img690.imageshack.us/i/screenshot9q.jpg/

This is right outside GNR, the Behemoth fight area. You'll notice in the first image, the street won't light up, but I do nothing but swing my camera a little to the left of Bittercup and it lights up. This issue is all over my game, interior and exterior. Using Fellout (which I know cannot cause this issue) and Wasteland Street Lights (which also shouldn't do this, since interiors do it too), but nothing else effects lights to my knowledge.

Did some fiddling around with Gary Bash, FO3edit and messing with what was and wasn't on, and it does appear to be Wasteland Street Lights doing it to the exterior areas. Not exactly sure what is causing it to interiors still though.

What is your specularity fade set at?

If it's low, try increasing it.

Do you have HDR turned on? I was having the same issues, inside and outside and the only thing that stopped it was turning off HDR. Never figured out what was causing it. I tried everything, GaryBash, FO3Edit, etc.

This seems to be a problem that already exists in the game, my fallout street lights makes it show up. I believe it has something to do with multibounds, anyway I'm looking into it.