This has been an issue for me since 1.15.0 and it is similar to a bug in release cycles of 1.14. Red and white lines, usually over large flat areas when looked at from above.
To recreate, fly up to an area with elytra or in creative and look down at the ground.
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Looks like this one? MC-1794
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This is a technical support issue, which we're already tracking in MC-1794, so I resolved and linked this ticket as a duplicate. We do not have the resources to provide you with technical support.
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