You made a late return and the depositary bank caught it and called you on it.
Your bank was not under any obligation to return funds to your customer. New York's version of the UCC, at section 4-404, reads:
A bank is under no obligation to a customer having a checking account to pay a check, other than a certified check, which is presented more than six months after its date, but it may charge its customer's account for a payment made thereafter in good faith. (Emphasis added)
The "requirement" that a bank refuse to pay a check over 6 months old has been dead for a long time. Some will argue that "good faith" requires you to have positive information that your customer wants the check paid. That might work in theory, but it assumes that you even see the date when the decision is made.
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8