I have a weird problem with my lighting

So i am trying to create a 2d paper scroll game. While i press to play my game the lighting is ok but while the time pass(like 0.1 secs) the whole game starts to brighten up like christamas here some photos of the start of the game and after 2 secs . Any idea how i did that? or how to fix it? Any advices will be helpful thank you

Its probably your exposure settings. I made a quick video explaining exposure.

thank you!