Sun affects both openarea and dungeons (old version)

[CrossroadInTheVoid]

Still working on crpg, using love2d and 3DreamEngine.
There are two types of locations in my game: open areas and dungeons.
Dungeons are affected by chainging day time and this not that I want to get. I do not understand if gamma or exposure makes dungeouns too dark even with manually created lights at night. Looks like that's not sun: I've switched it off and got the same result. I know about lib:resetLight(noDayLight) functionality — does not help. May be something changes gamma or exposure during day cycle somewhere inside 3DreamEngine? I've tried to find but got no success. Do you have any ideas?