The previous license expired at the end of 2016 and I’m sure negotiations would have started before then in anticipation of the uninterrupted publication of new novels.
I don't want to get all "Batman's a scientist," but Meyer's involvement in new Trek, with rumors that could've been this miniseries thing, date back to February 2016. Just because we first heard publicly that CBS and Paramount were thinking about re-merging recently (and heard that not everyone involved actually wants to even more recently than that) doesn't mean this couldn't have been an anchor slowing things down behind the scenes for a long time.