End Towers spawn underground

I entered the end on my world in the snapshot for the first time, and my spawn pad ended up being at the bottom of a near 300 block tall island. I got to the top and found the portal, but no towers. I went into spectator mode and found the towers had spawned about halfway down. As well, below them at the bottom was what looked like another set of towers that had tried to generate and ended up being only about 10-15 block tall stubs at the very bottom of the island.