End platform in the middle of the void

I had beaten the dragon and was terraforming the End central island in order to make the next dragon easier, and came out to put some End Stone in a chest. When I went back through the portal in the Stronghold, I dropped onto a newly genarated End platform in the middle of the void! I managed to bridge across to an outer island and use a gateway to get to the main island, and it hasn't spawned me in the void platform since, just my normal one. I have uploaded two pictures, one from the platform and one using a Spyglass from the central island towards it.