Siennas Staff Illusions

is there a reason that the conflagration and fireball staff have just one illusion?
the beam bolt and flamestorm staff have each five or six Illusions.
or do i just have bad rng and dont get any?

According to this, we only know 1 Illusion on those staff (Apprentice, as Sputtering is the base one).
So if it’s bad RNG, it is for everyone…