Flat creative world has mixed with survial

Hello, In my minecraft Windows Edition 10 i have found a bug in one of my worlds. This bugs has never happened before. In my Flat, Creative world for some reason it is glitching out and adding a surrounding of a survival world. Before i got into the game it moved the world all the way down to the bottom on the menu and some how mixed it up with a survival world I had from December. It was still a survival but it also had the creative worlds name.