> Doesn't Lambach's use of the Legion granted ability falls under the
> NRA rule?
Yes.
> So that he can only put one Disciplin card in play per turn
> (and untapping afterwards of course).
No. NRA restricts you to one action per card in play that grants you
the ability to take that action. If a vampire has 10 Legions on him,
he can take the action to put a vampire in play 10 times per turn,
once per Legion.