Just going through some older items. This was an interesting find, and I'd like to see more versions. Apparently, there wasn't any postage, or it fell off? In any case, it was hand cancelled, then someone placed a stamp on top to cover the lovely return hand.
So curious. It was accidentally mailed without a stamp. It was returned to the sender, who just put a proper stamp on top, then mailed it again? Looks like it to me.