Terrain disappeared around the player after loading a Hardcore world, causing a void death

Brief description of the problem

After joining a Minecraft Hardcore world, my player immediately began losing health for no apparent reason. Shortly afterward, I died. The death message stated that the player had fallen out of the world.

However, I was standing on the surface of the world and was not intentionally falling into the void. It appeared that the terrain around and underneath my player disappeared, causing me to fall into the void.

My cat also died apparently by falling into the void.

After my death, I entered the world in Spectator Mode and returned to the location where I had died. I found that a very large section of the terrain around and underneath my previous location was missing, exposing the underground layers and the void.

Steps to reproduce

1. Open a Minecraft Hardcore world.

2. Join/load the world.

3. Observe the player's health after loading.

4. The player's health begins decreasing unexpectedly.

5. The player dies and the death message reports that they fell out of the world.

6. Enter the world in Spectator Mode.

7. Return to the location where the death occurred.

8. Observe the surrounding terrain.

Expected result

The player should load normally on the surface without taking unexplained damage. The terrain underneath and around the player should remain intact.

Actual result

The player's health begins decreasing immediately after joining the world. The game reports that the player fell out of the world. After the death, a large section of terrain around and underneath the player's previous location is missing, exposing the underground layers and the void.

My cat also died apparently by falling into the void.