When a player loads chunks quickly, the render engine will unload chunks around a seemingly random rotation point. It's clear that this is a bug with optimizing rendering only visible chunks, but it seems that it tries to cull chunks that are visible as well. This is an extremely easy bug to observe, simply go in spectator and fly straight, then start turning in one direction, this also works with any FOV (although it is a little more difficult to see with 30, it isn't really that hard.)