Yup, funkery afoot in the postal system. Just today my NYS Star tax refund check came, it's the kind of envelope where you tear off both serrated ends and unfold to access the check, "somehow" one end was torn off, the end that will let you look inside to view enough of the check to clearly see how much is was for. The "lady" who delivers the mail here isn't happy with me, long story. But it's not the first time I've had "things" happen to my mail. Remember the drunk mailman in the movie Funny Farm? She's the female version of that, drives like that and you can hear that old mail van we have here flying up the road.
This spring I too had a package that had been cut open, contents removed but it never made it to me, somewhere in the system the empty package was sent back to the sender, they called me, told me what happen and sent me another with tracking. Unfortunately there was no tracking on the first one so there was no way to track how far it got before it was sent back to the sender.