My Brother is building a Medieval City, and we would randomly notice a staircase went missing, the pond we had made gradually deeper, was suddenly all one block deep, he fenced in an area and they also randomly went missing, also another issue he has had was fire spread automatically turned itself back on after he had it off twice and he had to do some rebuilding due to this. Neither of us can explain this, the only thing I can come up with is a saving issue. please help?