When gravity affect blocks fall on player, player falls through blocks under them. If there is no cave under the player, this means that they will fall through the world, and die in the void. This can happen in all dimensions, and in all world types.

Important note, the player does not have to be directly beneath the gravity affect block, they simply have to be touched by it. Also, the falling block only needs to be 1 high, and can be at eye level.

To recreate, stand under a stone floor with sand on top, and remove the stone, letting the sand or other block fall. You can also walk into a falling sand block or other block, and the same thing happens.

What is expected: player remains in position if block can not push them out of the way, and the plater will take suffocation damage.