Giant square cloned blocks teleport into other pieces of land.

It is like someone is copying and pasting large square chunks of land over other pieces. I was out hunting for food when I found half of my farm in the middle of nowhere so I rushed back to my house but my farm was still there. There was also a tall huge perfectly square peice of rock with grass and trees on top in the middle of a previously flat area. I looked around but all the mountains were fine. Pls fix