Non-player entities fall through solid blocks in void superflat worlds

When creating a superflat world comprised of only a layer of air, non-player entities affected by gravity such as items, armor stands, mobs, etc. will fall straight through solid blocks and out of the world upon being spawned.

Does not appear to be biome-dependent. Creating a void preset with a different biome produces the same result. Two layers of air makes no difference, but 100 layers of air appears to prevent the issue from occurring.