It's quite normal. It's to do with a sequence of ghost or parallel entries that have clunked their merry way from Amadeus to SABRE. I've often seen it and it works in the wash eventually. You may find that classic.checkmytrip.com looks a bit of a mess too. The only reason I would worry is if I changed the AA or US legs after initial booking, since the previous SABRE entry may be left alive rather than killed off. I think it has been raised before, our Alaska friend may find examples.