mincraft map error

I've been playing the wild since version 1.15 of Minecraft, and when I make or update a map from the Snapshot version, I see a strange scratch on the map like the attached picture.

I tried optimizing the world and entering Minecraft files and copying the world... 1.16.1 It's the same in the official version...

 Is it a bug in the game? Or is it something I can solve on the computer?