New 1.19 chunks creates chunk borders with old existing 1.16 chunks

Did the terrain persist when you flew up to it, landed on it and started breaking/placing blocks? There is a common bug where some chunks would generate like that visually on old worlds but once the player comes up to them and the game refreshes them, they disappear.

I have the same chunk errors in my old world. It looks like in the image and persists. When flying around the game sometimes doesn't fully load chunks in one area and there end up being lonely chunks that don't attach to the main land. 

I still wait for the reporter response. 

Sorry for not responding sooner. The terrain was created when I flew past it.

This happened to me too on my world started in 1.16. Never modified and survival only.

Thank you for your report!

However, this issue has been temporarily closed as Awaiting Response.

Could you please export and attach the world in which you experience the issue?

This ticket will automatically reopen when you reply.

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Hi, world is too large to attach here, but here is the download link: https://www.mediafire.com/file/odrf86wtjmucoxo/Survive+221.mcworld/file

I am not able to reproduce the issue. If it still occurs on your world, could you please upload here a newer save of the world?