Can't find a more official source than Reddit, but here goes:
> It's because the position of each polygon's vertex (corner) is only calculated at a very low precision. Once the polygon moves (or the camera) the vertexes will stay at the same point, until they're closer to the next and suddenly "jump" to the new position without transition. Newer graphics hardware could interpolate smoothly here with more in-between states (that's where all the talk about "floating point precision" came from in graphics).
0. https://www.reddit.com/r/gaming/comments/bkedc/heres_a_quest...