This is intentional. I think the plans are that SpaceX would be directing the first stage to de-orbit and enter the atmosphere with an "incorrect" trajectory, so that if the landing burn fails the rocket will be safely sent out to sea. Part of the landing burn is a redirect maneuver, so that the rocket will always have a crazy angle when it comes in, but will also keep land/people safe.
Perhaps that's not what happened here - it sounds like Elon later explained that there were high winds at the landing site that might have caused the heavy lean. However, what I said about the last minute divert maneuver is possible/probable for future landings. Here is a recent discussion about it: https://www.reddit.com/r/spacex/comments/3xzn7s/my_previous_...
