When generating a world and quitting the game right before you'd enter it (can be achieved by repeatedly pressing Alt + F4 on windows), then reentering that world the player ends up 0 0 0.

This seems to be caused by the world storage changes in snapshot 23w42a.

Inspecting the level.dat file in an NBT editor reveals that the Data/Player entry is entirely missing, indicating that the game quit before initializing player data.

Attached is a copy of a half-initialized world.