I noticed in TE4 that for indoor matches the crowd has a lighting issue. When applauding after a point, the people suddenly appear a lot brighter when clapping than they do when sitting still. Once the clapping stops, they immediately become darker again. It looks like a lighting issue with the movement.
It only happens in indoor matches, and only with the crowd (the empty seats don't change in brightness).
It's rather jarring in-game.
I made a video of it here