Has an ATM ever given you the wrong amount?

This question popped into my mind when I withdrew cash from my PayPal account and took it to my bank to deposit. The ATM spent all of 10 seconds counting out $400 in $20 bills. I do count to make sure the machine didn’t cheat me, and I have never seen an ATM make an error in either direction.

The teller, on the other hand, required several minutes to count the bills twice before noting on her computer how many $20s she was adding to the cash drawer, and processing the deposit.

And I have seen tellers make a counting error even after a double count. It’s rare, but it happens. More often, I’ve seen them have to do a third or even fourth count because the first two didn’t seem to match. Brand new bills can easily stick together. It’s not hard to count two of them as one.

I’ve also made counting errors before handing the teller the cash. Have you ever been cheated or gifted by an ATM? If it cheated you, were you able to prove it? If it overpaid you, what did you do? Do you have any idea how the machine works to avoid two bills ever being counted as one?