Auto Exposure Problem?

I have rendered a video and there’s seems to be an auto exposure problem. At the beginning of the video there is a slight flicker, such as dark and back to bright again in the first 1/4 of a second. This happens every time the video switches to another camera. I have turned auto exposure off so this shouldn’t be happening. I also tested this by turning off Auto Exposure in the camera and also Post Processing, but the problem still persists. Is there a way to stop this?

It might be the shadows. There are a some dynamic shadow effects that are iterated on over several frames, like DFAO. Test it with shadows disabled on all lights or set all the lights to static and see if the problem persists or not.