The confusion comes from the overloading of the term "higher vampire". It has two meanings. First, a group of vampires who are above lower / more animalistic types. These higher vampires are sentient beings. Then there are "higher vampires" who are unique even amongst the first group. I'd prefer to call them "high vampire" to distinguish. These are like Regis. Bruxae are higher vampires in the first sense, but not higher vampires in the second sense. Confusion is apparently built into the world itself. I.e. even people in the world mix things upIf bruxae are indeed 'higher vampires' in the games, then why are they 'mortal'? It seems that further classification is needed.
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Yes, I saw that. But CDPR have some inconsistencies, which for me have less weight in comparison with the books. I.e. if the books say strictly otherwise, for me they win when it comes to lore. And they say that vampires are normal species and not turned from people. The rest is up to deduction.Read passage above.
The only known exception I think is a striga, which is a special curse case.