I spoke with the person who did the transaction.  She was doing two different work order for the same serial controlled product.  She finished the first one and closed the work order.  She was in the middle of finishing the second and realized she had given  its serial number to the first one.  She assigned an "error" serial number to the second WO then backed out of the finish production.  She re-opened the first WO and then backed out of the finish production, and refinished with the correct serial number.  She then finished the second WO again with the correct serial number.
The GL is showing two finishes for the first and 2 finishes and 1 back-out for the second.  The serial number file is correct, with one for each with correct serial numbers.