I was playing the latest snapshots after picking up the game from years of not playing it possibly from update 1.6.1 when horses were added. I created a long road for horses to transverse and was quite proud of it, the crown of that save but lost interest due to life events. Now after picking it up I had a good save in the middle of the ocean on an island but after venturing out in the world I noticed an odd split in it. The world had suddenly changed the environment of the ocean into a swamp off in the distance, I let it be and started venturing off in a different direction and noticed that there was an old village that hadn't had any work stations and the villagers and the buildings looked old not like the updated ones. I went back to the swamp and notice the trail of torches and recognized it as my old road, I followed it for a bit and made it to one of my old safe houses the game had mashed my two worlds together. I had good memories of that old world and held on to it,  though a good portion is gone now covered with the new world save. I think they both had the name new world that it combined them but I wanted to report this in case anyone else may have there memories covered by this bug too