I think this is most likely human error which means Lockheed Martin is at fault and will have to pay a fine. The weapon took a ridiculous route with a number of outside contractors on its way back to the intended destination. Apparently companies make shipping mistakes all the time.
"..from Orlando International Airport in early 2014 to be used in a North Atlantic Treaty Organization military exercise..missile was sent to Spain and used in the military exercise. But for reasons that are still unclear, after it was packed up, it began a roundabout trip through Europe, was loaded onto a truck and eventually sent to Germany."
"...packaged in Rota, Spain, a U.S. official said, where it was put into the truck belonging to another freight-shipping firm, known by officials who track such cargo as a “freight forwarder.” That trucking company released the missile to yet another shipping firm that was supposed to put the missile on a flight originating in Madrid. That flight was headed to Frankfurt, Germany, before it was to be placed on another flight bound for Florida."
"...officials realized that the missile had been loaded onto a truck operated by Air France, which took the missile to Charles de Gaulle Airport in Paris. There, it was loaded onto a “mixed pallet” of cargo and placed on an Air France flight. By the time the freight-forwarding firm in Madrid tracked down the missile, it was on the Air France flight, headed to Havana."
Missing U.S. Missile Shows Up in Cuba