when you are playing in a world and your building if the world crashes or you went for a while the world wont be changed latestly (your builds wont be saved) speacally in 0.14 because world crashes ALLLLLOOOOOTTTTT !! it was not like that in 0.13 or 0.12 this happens for me on those devices ipad mini ios 8/ ipad pro ios 9/ ipad 2 ios 9/ iphone 4 ios 7