There are no sources that can legitimately validate this profile - it's bogus, invented as an "explanation" for the "origin" of the clan Macduff (which was older by at least several generations).
The Macduffs were, in fact, descendants of King Dubh (Duff, Duffus) of Alpin (d. c. 967) through his son Cináed mac Dub (Kenneth III).