End gateway on the main island generates fine. However, gateways off the island in the outer islands do not generate at all. This is different from MC-185185 which deals with end gateways on the main island. Observe the following scenarios:

1. In the survival realm, I made my way to the intended spawn location of the end gateway after end busting for some time. No portal was visible or present when I walked into the exact space it should have been in. 

2. In a download of the realm I had made before anybody had travelled to the end, I travelled to the end and used commands to teleport in creative mode to the same location without killing the dragon. The portal was there. Don't know if the dragon is related, probably not, but figured I should mention it.

Seed: 1013248190

Cords: -2472, 64, -1721 (In the End)