There are a few bugs related to this:

1. Minimizing the game window rebuilds the world as though you are just loading into the world when you maximize it.

2. Minimizing the window will sometimes log you out of the xbox live server when you maximize it.

3. Minimizing the window when in a realm will kick you from the server when you maximize it.

4. When playing a multiplayer game with friends on your own local world, minimizing the window will kick others off and they will have to rejoin.