I was exploring my world when I came across several unusual instances of world generation between different biomes (shown in the pictures below). The biomes would be cut off in chunks rather than the normal smooth generation. I tried restarting the game and /reload, but neither did anything.
The pictures below were taken within 1000 blocks of xz:0 0. As some background information on this world; I had some past problems with it (it disappeared for a while), which led to me doing this method to recover my world: https://www.youtube.com/watch?v=DDEkJG6ZYeI. I'm not sure that has anything to do with this bug, but if it does, then there you go.
This can be 1 of 2 things. Either you are playing on a world originally created in an older version. In this case, some chunks were generated before the update, and then the rest later after the world generator was updated.
The other possibility could be bugs such as MC-315.