Blocks resetting

All blocks that have been mined or placed reset after I save and quite to title. Everything in my inventory remains and I'm in the same place as when I exited.

What I expected to happen was...:
When I start playing Minecraft I expect that all blocks will be in the place they were when I last played.

What actually happened was...:
All blocks are reset to their original position.

Steps to Reproduce:
1. Create new world
2. Dig up some blocks
3. Place blocks in another position. (In a stack for example)
4. Save and quite to title
5. Select single player
6. Select world
7. Blocks are in original position as if I never dug them up and stacked them.