So - I realise this isn't really "proof" per-se, but as per HH's guide, Stage 6 should require only about 115 RES to resist. I don't have the actual numbers, but I assume that's reasonably accurate. As can be seen from this screenshot, none of my five champs resisted, and all of them have well over 115 RES. Mithrala has like, 700 RES.

Yes, theoretically this could just be phenomenally bad luck, but the odds of that are rather small. Assuming a 3% base chance of landing debuffs, the odds that all five land are about 1/400000. And, as can be seen from the debuff counters, clearly they landed many more times than just once throughout the fight, since Mithrala has quite a few stacks.

This goes a long way towards explaining why my runs sometimes fail despite succeeding frequently. If I have the misfortune of not resisting a debuff early on in the fight, it can completely warp the rest of the fight.

i

i can confirm that that is definitely what's happening, though i've been assuming that it's a partocularly annoying feature rather than a bug.

I hope it's a bug that can be fixed 😉

A good assumption, I would say.

Something you can investigate for us? Would like to know if this is a bug or if it's intentional. If it's the latter, it significantly diminishes the value of resistance for this fight.

I have investigated and return with news! :)

This is NOT supposed to work in the way it currently does. Resistance should be able to prevent extension of the debuff. It is now on the known bug list to fix.

Awesome!

Does anyone know if this has been fixed?

Both for the application AND the extension?

it has been fixed for the extension and as far as i know the application has never had that issue.

correct, as of version 6.10. 

Thanks for letting me know guys!

So champs can actually resist now the application AND extension of the Iron Brand?

That is correct, yes.

Thank you!

I find it incredible that my Mithrala is ironbranded with Siphi as lead.  How is this even possible with 800+ RES?!

As far as I know, there is a minimum chance of 5% to land a debuff, even attacking a 900 res champ with 0 accuracy.

3% actually, but the ironbrand lands VERY consistently.

Can any developer please clarify?

So not a Developer. But the extension bug is gone. Really it's just the fact his Accuracy is very high for a PvE enemy, and he gets a lot of attempts over the course of even my 3 minute fights with him. My Mithrala occasionally picks up Ironbrand and she's well above that 800 Resistance, she's about 1000 with her Aura. I will say she's always at way under the number of stacks my Helicath has though. :)

Thanks!  I appreciate you taking the time to answer.

Your response does make sense.

What does Ironbrand do to our champions?  I cannot find that anywhere.  I am guessing we don't want it on our champions, but why not exactly? 

Increases the damage all of his moves do, per stack of Ironbrand.