Note the wording when speaking to Gnomon!
Note what he actually says to you and what you have to say in return to even get given the quest!
My problem with this quest is that you're not deceived by Gnomon into doing Evil but indeed for a great many characters {seriously how many people actually take Follower of the Silver Flame apart from Cleric/FvS Archers anyway?} have to tell a blatant lie to a supposed Cleric of that Deity just to be given the quest in the first place!
Knowing this I do not accept shares for this quest on characters that aren't Silver Flame followers either!
P.S. Yes I know my Hotbars are a mess!