What happened was one person played the same five numbers TWICE. I've been seeing this strategy lately from players. I mean it's smart. It's a preemptive strike incase you have to share the jackpot so you end up getting the bulk of the money. It was split three ways, 18K a piece, so that one person got 36K and the other got 18K. If the double player only played their numbers once they'd have got 27K; so by playing it double the doubler got 9K more.

People do this all the time for pick 3 and pick 4 but that makes more sense than jackpot games because the odds are much easier. 

People who do this for jackpot games I feel are people who play the same numbers every day so it would make sense to just play it twice. But if you're playing different numbers all the time you can't be doubling up on all of them. 

Sometimes doubling up could be an accident. Happened to me once. I handed the clerk the same slip at a different retailer. But most of them are intentional to maximise winnings.