This is not an important issue by far, but I figured it wasn't intentional.
In QP, I've noticed this small and faint slope at the bottom of the board. It's been there for a while. This only appears in QP and no other mode (that I know). I really see it in The Museum, due to how bright the background is. I play on low graphics also.
I'm not sure if a course of action is needed because it doesn't affect gameplay, however it is a good thing to bring up if this is an aesthetical problem.
I assume