End gateways teleport player below main End island

Summary:
End gateways always teleport the player below the main End island after they have been used for the first time.

Steps to Reproduce:

1. Travel to the End and defeat the ender dragon to generate an end gateway.
2. Enter the gateway. Observe that it teleports you to the outer islands.
3. Enter the exit gateway. Observe that it teleports you below the main island.
4. Enter the main island's gateway again. Observe that it teleports you below the main island again and not the outer islands. 

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Original Description:
Going through any end gate, it will take you to 0, 0, 0 in the end