Based on previous rulings on Herod's Treachery:
1 2And the thread referenced regarding Joseph:
1And the general way we treat these abilities and brigades, I would rule thusly (if anyone has a different idea, let me know):
Being
immune to brown brigade means that it "cannot be targeted by an ability that is on a card to which it is immune or on a card played on that card" (The REG, Immunity, How to Play). If immune to the whole brigade, as in this case, that includes characters
and enhancements by definition. Even if it is played on a Gray character, Scattered is still Brown.
If you were immune to just Brown
characters, then you would only be immune to Scattered if it were
played by a Brown character (or at least one that was part Brown). That is not the case here, however.