For example in Reachwater Rock, the ambient lighting changes whenever I step through the puzzle door. I'm probably stupid, but I simply can't figure out what's the trigger. The problem is that I have darkened the dungeon by adjusting the lighting data, and the dungeon is otherwise just as dark as it should be but after stepping through the door it gets way too bright.

Any help, anyone?

You can set lighting settings with Roombounds, so once you place those you can have each section of your map look different if you wanted to. (I think that's what they did at Reachwater Rock)

Thanks for the quick help, that's exactly what I was looking for!