Cloning blocks makes the positions in target area have two identical blocks in one position in client. And the water background layer disapears in client.

These blocks need to be broken twice to become air. And they will return normal after restarting the game.

Maybe it has something to do with MCPE-136537, because when trying to reproduce MCPE-136537, we often meet similar behavior. And in this bug, the water background layer also disapears in client.

How to reproduce: Clone some blocks with commands, and try to interact with or break them.

The attached videos show what happened in my game.