This is anecdotal, and not explicitly about ATMs, but I have had those "Pay your bills here" machines at 7/11 and other convenience stores mishandle my money a couple times. It would report I paid $150 instead of $200, missing a single $50 note.

This was resolved after about 2 hours on the phone with the company who manages the machines, but I still don't use them anymore.

Years ago depositing cash into envelopes which would slide into the machine, once or twice I had the deposit amount “adjusted” after the fact.

How can you prove if it was you or them that miscounted?

Modern “envelope-less” machines do not have this risk.

Counting cash by hand is surprisingly error prone. I ran a snack bar in high school and I would hand-count a large pile of grubby $1s before bringing to the bank. About once a week the total from their counting machine would not match my tally. I think even once it was the machine that got it wrong.

If you’re face to face with a human you can error correct before the pile of cash disappears.

The coin counting machines in the US closed a couple of years ago due to a class action suit for chronic short-changing: https://www.bankrate.com/finance/banking/banks-expel-coin-co...

Debit card skimmers are very common in ATMs, as are cameras to catch people entering their PIN. Although I have never seen an ATM where you can deposit money at a grocery or convenience store, and so I’m not sure what the potential attacks are for such a situation, I would imagine that tampered-with ATMs could capture other information or remove money from your account.

See https://krebsonsecurity.com for a ton of articles about various skimmers and scanners that have appeared in ATMs and gas pumps.