Call the originating bank and ask for the additional information. They might hesitate with privacy laws, but explain that it is in regards to the wire and a possible OFAC hit. Hopefully they will be willing to assist you, if not the OFAC hotline service personnel will want to know this and can contact them on your behalf, but they prefer you to get the information first.
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I have many opinions; some are good, some are bad, and some don't contradict.