This ability seems to pull randomly between -50 and +50 fervor and fervor overcap, so about 50% of the time it actually debuffs the player that it lands on. It is said on the tooltip to only give positive fervor and overcap, something to the tune of 36 fervor and 50 overcap, but in practice will often nerf the player receiving it.
I'm one of his cf targets in raid, can definitely confirm the negative is happening. Casting it from my alt account dirge to my main sitting in guild hall the amount of fervor is different every cast, including negatives
