No one does standard attacks before mystery due to a passive, as far as I am aware. What happens is they cast whatever passive action is, then the mystery always comes first, and then standard attacks. If the passive gave an extra attack, then it will happen after the first attack, assuming some other mystery doesn't interfere. So that part is not a bug.

But I believe both the taijutsu leech and lack of text regarding it using life have been reported already.