NOTICE:
As of recent snapshots this no longer happens but I don't know for sure if it truly is and will just randomly happen some day.

Overveiw:
I was playing minecraft and I was fiddling with the new command blocks when I noticed I no longer could open them. so I saved and quit, but when I came back on the a chunk had reset.

What I expected:
For my chunks to NOT disapear _

What happened:
they did T_T

Recreating:
I dont actualy know how this happens. just happens every time i add a command block anywhere. there are no commands that are meant to be removing that chunk. However it has happened every time one of these things happened.
1. I die
2. Entitys disapear and I reloged to make them reapear (They did but chunk didnt)
3. Command blocks no longer open (they opened after relog, no chunk though)

What i think happened:
I think the chunks might not have all saved so when i reloged they reverted

Plead:
I want to work on my redstone mini-game. plz fix this :'(

Game Output:
In the attachment. note there is a TON of excess redstone running in the background.