Its not a bug, it was discussed earlier today in other threads
Then apparently it's user error.
I'm betting this is what happened. From what I know about the DLC, I don't see it as feasible for him to finish it in 30 minutes.
Also, funny side-note, the only written user review on Metacritic for the xbox is a 5. His reason? He hasn't played it yet, so he's just placing it there until he does.