I've found this and this, and a few incidents relating to PNC ATM, but none applies to me because the issue is I don't know accurately how much I was trying to deposit. I always count it, but I was in a rush, and for the only time that it matters, the ATM ate the cash. I actually counted them a few days ago, so I can vaguely remember (estimate) how much that was.
I tried to deposit some cash into a PNC ATM after office hour. It declined and spit back the big bills ($100 and $50), but took the rest. The screen said "Invalid bill or Exceeding amount". I took back the bills it spit back and went ahead with depositing the rest of my cash ($20 bills). This time it took most bills, spitting back three, and it was in the processing of counting (based on the sound the ATM was making and that the screen was saying processing) when suddenly it went "Transaction cancelled". The ATM just then immediately went to the starting screen without any receipt or anything further.
I contacted their customer service immediately, gave them my best estimate how much I was trying to deposit (say X dollars, even underestimate to avoid them thinking I'm scamming). They filed a dispute for me and deposit X dollars into my account, but they told me that without the accurate amount, it's very likely the dispute will be declined and the bank will take back those X dollars. I realized my mistake and tried to note down from what time to what time it happens and everything that happened during my transaction. I've try going to that PNC branch the next morning, attempting to provide more information, and the banker interrupted me saying there's a dispute already, essentially repeat the same thing customer service told, and essentially I'll lose the cash and there's nothing I (or they) can do, and that they can't just open the ATMs and investigate.
I'd think that banks would easily have some kind of logs to keep track of the funds inside ATMs before or after each customer transaction with timestamps and all sort, which can easily be cross-checked with security cameras. I don't work in fintech, but it sounds to me like there will be some method to solve this matter, as daunting and long as it be. Is there anything else I can do?