I started up a new world and began flying around, and I spawned in an ocean biome. So I tried to fly to dry land, and I came across this strangely generated chunks. It's the same chunk generated over and over again. And so, I finally found dry land (it was in fact that Swampland that I found first) and the same thing was happening. Swampland chunk, then that same Ocean chunk. But the Ocean chunk would then be replaced by a new Swampland chunk. I got a picture of the first bug below, but it has stopped since then. Probably just something that happens when you first generate a world?