Chunk seemingly unrenders for no reason

I have this one spot in my house that will unrender at the top of the stares for seemingly no reason, x-raying to my front path. I have no idea why this happens, nor any idea the steps to recreate it. I don't know if you would want a world download to that spot to investigate or something, but I sure can't come up with a good reason for it's happening.

Video and images attached. (Top of stairs w/ and w/o the chunk missing, and front path.)