Minecraft Weird formations that other players cannot see, and mcpe crash. (Proof in downloadable video and image)

Some players will find weird formations that other players cannot see, even next to the person who saw the formation, also I recorded mcpe crashing while making the video to show you the issue, just use this link to download the video: https://www.mediafire.com/file/bx7qx57uhg1i0gw/Minecraft_2019-12-08_21-25-26.mp4/file