When traveling past X/Z = 370,720 in the end dimension, one can see that the terrain generation stops entirely. At X/Z = 524,288, terrain generation resumes before it eventually stops again. This bug has been present in Minecraft since snapshot 18w46a.
Here is a YouTube video by AntVenom where he explains the bug in detail: https://www.youtube.com/watch?v=91Feq0dHw28
Believe it or not, Antvenom was not the first to discover that.
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We're tracking this issue in MC-159283, so this ticket is being resolved and linked as a duplicate.
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