This came up about 2 years ago, some cards were getting anniversary bonus just once and others get it every year. I think Frequent Miler or another Boarding Area blogger had a post on how to see which type of card you have, and it might be in previous threads covering this card and its history as well.

It was somewhere on your account page that discussed "How My Rewards Work". IIRC it was random as to which card you got, i.e. not certain application links or time period of applications that didn't get the bonus more than once. But I could easily be wrong on that part. And this could be something unrelated of course, too.