The islands in the End transform into endless mainland after X/Z = 999,0000 or so

Steps to reproduce the issue：

1. Create a new world

2. Enter the End

3. Teleport to the position

/tp @s 9991000 100 0

or:

/tp @s 0 100 9991000

It appears closer when X coordinate = Z coordinate.

/tp @s 9581500 100 9581500

Expected Result:

There will be the mainland as the screenshots show.(Seed:8698768889334720510)

I created several worlds and they all have the same phenomenon.