Crackpot time.
I was thinking, perhaps Iyokus is working for the consult.
Possible ways of avoiding detection by Kellhus;
He avoided Kellhus for pretty much the entirety of PON,
His passions are vestigial thanks to chanv,
He is used to having see thru skin so he knows all about the 48 face muscles etc.
Hiding your true intentions is as per Yatwer's spit is a side effect of consorting with demons, or a basic incipient glamour in the arsenal of the Daimos.