Hi! So that's one the weird caveats/mistakes in the game: prior to BaW (and even with the expansion) the game devs still have him marked off as a higher vampire (and then when BaW came out, they changed up the definition to bring back Regis). That said, as they still have Hubert marked off as one, even if by the BaW definition he's not, we still go with the game information and just note in the notes there the error/mistake.
Yeah, I remember seeing the cutscene where Geralt refers to a Katakan as a “higher vampire” to a guard. As you said, this is retconned in B&W, where Geralt refers to katakans as being lesser vampires in a conversation with Damien and the Duchess. A bit of a discrepancy here.
B&W changes the canon for higher vampires, but I do understand the idea of having Rejk’s page referring to what he is in-game. However, I would defend my change of rewording the infobox description from “higher vampire” to simply “vampire”; the latter is more general, and while “higher vampire” may be confusing for the reader by sending mixed messages of what one actually is, “vampire” is an inclusive term for whatever he may be. The broader meaning of it suits the ambiguity of Rejk’s race.
In terms of the trivia point I changed, I agree with your point that the original game’s description of him retconning B&W’s version is noteworthy and that my change - referring to the higher vampire description as “erroneous” - did need undoing. That said, I think the existing wording of it does need altering. Something like: “As a Katakan, Rejk is considered to be a higher vampire, but the Blood and Wine expansion retcons this by classing Katakans as lesser vampires”. This may, of course, need improvement too, but I believe that the wording needs changing on this page.
So I changed it around some to add the reference into the infobox itself. The problem is (and this makes terms even more confusing) is there's 2 "grades" of vampires: higher and lower. Katakans are still considered higher grades, as are higher vampires, but while higher vampires are higher grade vampires, katakans are not higher vampires (yeah confusion!).
It seems to me like Katakans are like a middle grade of vampire - higher than Garkains and Fleders etc, but not as high as actual higher vampires. Even higher vampires seem to be different, as elder higher vampires (i.e. the Unseen Elder) seem to be stronger still and are almost like their own sub-tier. B&W certainly made vampire lore a lot more complicated!
In general, CD Projekt games originally followed Wiedźmin: Gra Wyobraźni in using "higher vampire" as a term to denote all intelligent vampires (thus excluding ekimmaras, fleders etc). This was contradictory to the novels (where there are savage ones, sapient ones AND higher ones as a distinct subrace), so they tried to correct it. That said, dozens of people worked on the game, so I imagine miscommunication might have been frequent in such cases. Mind that one of the main writers had no idea of what type of vampire Orianna should be.