If you quit and copy maps on multiplayer it destroys haft the stuff built try it

I noticed this too. About one chunk is missing off of the borders. If a torch was on the "in" chunk, but it was attached to a block in the "out" one, you get a floating torch that is not connected to anything. Never tried, but i wonder what would happen to a bed, maybe it coild get cut in half.

(Excuse my typing, I am writing this off a Kindle where you cannot see your text)