There is one chunk in my game which reverts to a previous saved state, when it reloads after I have moved far enough for it to unload.

When it reloads, changes I made are there, but what is seen is the older state of the chunk. If I try to manipulate the blocks as if they are in the reverted state, then the changes show up. If I save the world onto a flash drive, or another location, then use that saved copy on another computer, or back to the original computer, then the reversion becomes permanent, no changes are saved, and the blocks again become accurate (appearing as the reverted state blocks.

The screenshot attachments are chronological, and demonstrate what is going on. In the first, you see the suspect chunk in it's reversion state. The torches outline the chunk. In the second, I have made some changes, digging up the raised dirt blocks, mining the cobblestone arch, and adding a cobb pillar.

The third shot shows the chunk after I have moved and returned, where the chunk has reloaded. It appears as if reverted to the previous state. The fourth shot shows that this is only a mask, and that the blocks are revealed as their new state, if I attempt to act upon the "reverted" blocks. For example, trying to put a torch on the raised blocks that have reappeared, no torch is applied, and the air state of the block is revealed. Placing a torch at the base of the disappeared cobblestone pillar reveals a cobb block, and no torch placement occurs.

This reversion mask persists with changes hidden but still active, even if I shut down the computer. I can log back in, and there's the new block, hidden beneath the 'mask' of the reverted blocks. And there is another curious element to the issue: shots five and six are taken right after loading the world, three seconds apart, the first showing the changes, the second reverting to the previous version (but only the mask.)

The seventh shot shows info about the location of the chunk, and also that this is not the original seed state for the chunk (the stone brick block at the

location of the block is part of the state to which the chunk reverts, as is the castle gate in the background (built in January 2013).

Shot eight shows the chunk after loading from the saved flash drive; note the torches placed on the raised dirt blocks showing it is no longer a mask. Short of this complete copy of the entire world folder, and subsequent reimport into the .minecraft/saves/ folder, the reversion is only a mask.

I have seen Issue files that are similar to this, but nothing quite the same. I also want to present as much detail as possible, in hope that you could find a way to recreate the error, and eventually solve it. Thanks for your tireless effort in making a great game even better.