Shulkers generating outside the world border bug out when trying to spawn

The bug

I teleported to the world border in the End. The game tried to spawn an end city, it failed/was restricted to halfway, making the shulkers teleport from the world corner to the spot they should be at rapidly.

How to reproduce

Seed: -681274902081396689
Coordinates: /execute in minecraft:the_end run tp @s 29999975.54 114.11 29999989.93 308.55 0.30