Yes, it is affected by lightning. I have implemented a “card” system, like a simple TCG, and every a card moves over cards, the underlaying cards are blurry and “fade back in”. Also, the environment gets reaaaly dark when the cards are displayed (right in front of the camera), since the cards reflect light. In some angles to the sun, they get even that bright, that you can’t even read the text on them 
And I just deleted my post-processing volume, but no change…