A maximal Saruman, when they are losing, concludes the signals are fake.

Because if they were losing they'd be a loser, and they're a hero.

Being a hero is the fundamental core of their personality.

If they're powerful they'll be able to convince some subset of their followers that the signals are fake, too, but at a certain point it's nearly impossible to pretend.

The further they do this, the more catastrophic the explosion will be when the ground truth inevitably punches them in the face.