The final writing credit was the result of a WGA arbitration between Roddenberry and Livingston (the latter got full credit for the screenplay). Alan Dean Foster also used the arbitration process to receive story credit.
Huh. Well, that's quite interesting. Although I've never happened to notice such a thing since then involving writing credits, I did see an early poster for First Contact
in summer 1996 that had a credit not seen when the film was released, either in ads or the film itself: "A Film by Jonathan Frakes." I wonder what that can be attributed to? Well, not for this thread.