So I created a superflat world using the Water World preset, and when I went into the world, I saw a bunch of structures where they definitely should NOT be. I saw Jungle temples, Desert pyramids, Igloos, Witch huts, Underwater Ruins, Ocean Monuments, and Shipwrecks. The Underwater Ruins, Ocean Monuments, and Shipwrecks I get, but not the other stuff. Not to mention this was all in the SAME WORLD where there is only ONE biome (Deep Ocean to be precise).

What's also worth noting is that the /locate command couldn't even find these structures, even when I'm right next to them. It couldn't even detect the Ruins, Ocean Monuments, or shipwrecks.

This doesn't only happen in in Water World, but it can happen in ANY preset EXCEPT for Classic Flat, Redstone Ready, and The Void. There are just Jungle temples, Desert pyramids, Witch huts, Igloos, Ruins, and even Shipwrecks littered around these preset worlds. The Ocean Monuments are exclusive to Water World, which I know is how it's supposed to be.

I don't know if any other structures generate in these presets, these were the only ones I could find. For all I know, there could be full-on Woodland Mansions. I hope this can be fixed.