Or, more likely, it's just the latest example of Star Trek not thinking through the flag ranks at all. In addition to the above examples of Janeway and Kelvin Pike, we have even as far back as TMP we had Kirk promoted directly from Captain to Admiral in an era where Commodore still existed, likewise TATV implied Archer was up for a promotion from Captain to Admiral, bypassing Commodore completely (which, IIRC is what they went with in the novels) or as recently as Beyond where Kelvin Kirk applied for a promotion from Captain to Rear Admiral, and would have gotten it if it weren't for his last minute decision to back out. Indeed, even in the novels, Riker was promoted directly from Captain to two-star Rear Admiral.