Minecraft not saving!

When I click quit to the the title and come back later, it doesn't save what I built/destroyed in the world, the items that I get don't go away though.

What I expected to happen was for it to save when I left

What actually happened was my game didn't save anything except the drops that I got.

Steps to Reproduce:
1. build something
2. exit the app or click quit to title
3. go back to the same world.