Anybody have a good suggestion for a return code on a cashiers check that was sent to the State under Escheatment guidelines?

Assuming this is your list of choices , I would go with "O." As your question suggests, there are no accurate choices, but a bank that accepts a cashiers check for deposit that is that old deserves to be put to some inconvenience; i.e. be forced to call you.

Thank you Ken. Somebody mentioned "Refer to Maker." Would you consider that a potential fit as well?

The Bank is the maker - that makes no sense.

True. I agree. I guess they were looking at it as far as perhaps the maker (bank) would let them know that it is old and likely got sent for Escheatment.