Occasionally when playing, I will see a block, or several blocks, that are inexplicably invisible, showing the sky behind them (even though I'm looking down) and either outlines of far-away mobs, or entire underground structures that I haven't explored.

Example image attached.
This example uses seed: -413209067 in creative mode.
I'm flying around, observing the area. A large amount of area in various biomes has already been flown over.

At time time I captured this screenshot, my character could not move, it got stuck at the coordinates shown in the image. The only way I could escape was to teleport somewhere else. Usually, though, when I fly or walk over the "invisible" surface blocks, the entire scenery disappears until I fly out of the boundaries of that "invisible" region. When walking, I could stand right on the edge and look down, but as soon as I stepped over the boundary, all scenery disappeared.

During a game session, if this occurs, it's repeatable. You can re-visit the invisible area. However, restarting the game, I cannot repeat it. I've observed this multiple times, in different games and seeds.