Bumping this - would really like to know the answer, as it significantly impacts how much I will use the champ.

Personally, I think it should stay. The fact that it doesn't take down the FK shield but does have triggers is interesting and unique for a Legendary.

I think it would be very cool if it did stay, but honestly, it feels a bit overpowered, and also somewhat unintuitive. The passive works similarly to reflect damage, except that unlike reflect damage, the person doing the damage is Brogni rather than the champ who actually took the damage.

That allows you to take advantage of all the possible on-hit efefcts without needing to sacrifice other stats on your champs. Only Brogni needs to wear the relevant set.

Hi - sorry to keep bumping this but this is incredibly important. Please provide some sort of answer on whether the passive was intended to work the way that it does.

why is this incredibly important. The worst case scenario is that you have to regear him. He is a nice champion nontheless and worth playing anyway for most (newer) players)

Because it will 100% determine how I use the champion. If the interaction is intentional, then his gear and masteries will be oriented towards CB. If it's not intentional, then it will be geared towards arena. And I'd rather not have to waste all of the silver on upgrading the gear for him to be on my arena team, and then find out that he's not worth using on CB after they change how the skill work.

kramaswamy.kr:  "Because it will 100% determine how I use the champion. If the interaction is intentional, then his gear and masteries will be oriented towards CB. If it's not intentional, then it will be geared towards arena. And I'd rather not have to waste all of the silver on upgrading the gear for him to be on my arena team, and then find out that he's not worth using on CB after they change how the skill work." 

If you are not running an Unkillable CB Comp, then you will most likely want to use Brogni in CB since he will offer you a chance to leap forward in prgoression....unless you are already a 2-3 key UNM team.  Regardless of the extra perks that his passive is proccing, he will greatly improve the survivability of most CB Teams.  I do not have the toons for any version of an Unkillable team, but I can consistently 3-key UNM with my old-school CA Team.  I expect Brogni to be the missing piece that allows me to achieve 2-key survivability.  

FWIW, I'm on 3-key UNM atm, just barely under two-key UNM. Not running unkillable, but without the passive interaction, he doesn't really fit on my UNM team (Martyr, Sepulcher Sentinel, Vizier Ovelis, Corpse Collector, Rhazin). The one I'd be tempted to replace is SS, since Brogni has the block debuffs ability on his A3 as well - but the problem is that he needs to be booked considerably to get his block debuffs down to three turns.

If the passive functionality is intentional, then I'd put him on either way, since that's a massive damage boost. But if it is going to be removed, I'd be much more hesitent - potentially needing nine books before he becomes properly usable.

The reflect damage portion of his passive is intentional as far as I am aware.  It is written into the skill description.  I am basically in the same spot as you: I do 28M-34M per key on Void depending on RNG.  I run Sepulcher (Lead), Rhazin, Kreela, FB & Valk agaisnt Void CB.  I make some adjustments for affinity bosses.  I intend to replace Sepulcher with Brogni for CB irregardless of whether or not his passive can proc the perks that the YouTubers are going on about: Like proccing a stun set every time one of his team shields are hit.  I am solid G4 in Arena and Brogni is not gonna make me competitve in Platinum Arena....so, the possilbilty of 2-key UNM is my best scenario.  

Have Fun however you use him!  

Yeah my main interest on the CB front is that his passive procs warmaster, which is quite a bit of extra damage. I think ultimately I will use him either way, I just hate having to use so many books before he becomes properly usable. I'm sure I'll end up having all of them go onto the A1 first :/

Stew has a vid out that says there is a note in the content creator discord that acknowledges that the Brogni passive procs effects from gear that were not intended,a nd that it will be fixed in a future patch.  No mention of WarMaster procs, but you can probably assume the same thing.   

Huge. Thanks for the update.

Murderinc officially confirmed that the reflected giantslayer procs are "working as intended" so will not change in the near future unless plarium changes their mind.  As WileyMan stated, the passive gear procs (i.e. stun)  were not as intended and have been or will be fixed.