The Issue

Occasionally, hostile mobs will spawn in broad daylight in newly generated chunks in a superflat world. I have only had this happen with low render distances; the last time it happened my render distance was set to 9 chunks. As far as I can tell, the erroneous mob spawning is localized to a single chunk each time it happens, and each time it has I have been sprinting and jumping or sprinting, which leads me to believe it's related to the constant chunk generation the game has to do so it can keep up with my speed.

Steps to Reproduce

1) Generate a new superflat world with the "Overworld" preset (it's the only one I've had it happen on)
2) Set render distance to 9 chunks
3) Set difficulty to "Hard"
4) Fly/sprint/sprint jump straight for a few minutes