World save Bug.

I was playing MineCraft Working on my main world add some stuff here and there. after I was done for the day I saved and quit and start playing again the next day. However I found Half of what I did last night was gone! And I mean half. the farm I made was cut in two the dirt I dug up was filled and the half the animals gone.

What I expected to happen was...:
All my work to be saved.

What actually happened was...:
All that work in vain.

Steps to Reproduce:
1.Start any world and do whatever (build, dig, break stuff, cut down a tree.)

2.Pause the game and click save and quit.

3.Reload the world. Note:It may not happen the first time but trust me it will happen.