Confirming the issue still exists playing on a Realms server under 1.13.1. Using the /locate EndCity command produced coordinates, but when I travelled to them, I found only a small 2-block-wide piece of a single end city room high up in the sky. Using /locate EndCity again now points to new coordinates, suggesting the end city was not able to spawn correctly.
Since 1.13 I have only found two "end cities" in my new world, both of which were only a single room with no end ship.
I attempted to attach a screen shot of the small piece of the glitched end city that I found, but I get an error message about a missing token from Jira when I try to do so.
I have observed the same issue on a whitelisted server I play on, in which some hoppers apparently spontaneously stop functioning until broken and replaced. Possibly related, I have also seen the same issue with furnaces, which when affected will not process ores even when loaded with fuel, requiring breaking and replacement.
Still no word on this issue? Elytra and shulker boxes are absent from my Realms world because of this bug. My wife spent literally about four hours wandering the End fruitlessly before we figured out what was going on, and we are hesitant to try again in the new world we created for fear of creating another End devoid of End Cities before a fix is released.
I strongly agree with the previous comment that says this is crippling for gameplay, and if this isn't fixed I don't know why I'm maintaining my Realms subscription. Even just some acknowledgment that the developers recognize the issue exists and are working on it would go a long way.