It seems like it is based on a combination of an earlier draft of the novel and the translator’s own ideas, because it contains things that were in Stoker’s notes but not in the final manuscript, and a lot of Scandinavian mythology is added. It is more overtly erotic and political as well.
This is probably going to sound like a stupid question, but did anyone actually check to make sure there weren’t any major deviations in the English translation of the Icelandic version?