I started loading a new sp world @ 16 chunks, normal settings.
Like since the first versions of the game I spawned in the sky, seeing nothing, and slowely sinking downwards.
It took a while for the first spawn chunk to load.
Then, when I started moving forward, only the first chunk loaded, but nothing more.

(see screenshot)
While moving to the unloaded chunk, I started slowely to sink downwards into the chunk.

Then after a while, suddenly a part of the chunk loaded and I was stuck in the chunk...