Regenerative blocks to a determinate height

Hello, this it's a report for a bug that happens even several versions ago.

What it's happening?

• As you can see in the video provided, when you do a cleanup using /fill with air blocks or just removig some blocks at Z height, randomly when you close the game it regenerate some areas (which shouldn't happen since in theory by closing the world, it would save the state of the world).

You can do a test, clear a large segment creating a void one (fastest way on End Dimension, clearing above end portal), and when you have done so, save the world, open it again and those segments will re-appear.

These segments created will be practically regenerable (at close, open the world), there is no way to remove them

Note: It also happens on mcbe servers