Fareed is unkillable in Pit of the Undying

Bug Name:

Fareed is unkillable in Pit of the Undying​

Bug Description:

In the quest: [Crow's Nest] Do Your Best, the third objective -Defeat the <Bloody Blue Mane> Fareed can't be completed.​

How to reproduce/proof:

In this video you can see that whenever Fareed reaches 75% HP he heals itself to full, twice, and when you reach 75% HP again he will be knocked down, but on this version, whenever he reaches 75% HP he will heal itself an infinite amount of times, making him unkillable.
I read that you have to use floating skills to knock him down (here: https://grumpygreen.cricket/pit-undying/) but it's not working. (Class is a ninja, maybe it's a class thing.) I have tried forfeiting the quest and killing myself to retake it and even relogin, nothing worked.

Without this I can't complete Fughar's Adventure Log, as this questline is tied with it.​

 

We have investigated Fareed's behavior and figured out that u must do max DPS in certain moments when he uses one skill
https://streamable.com/j20z2f
If u deal 10% dmg of his max HP (while he using that skill) he will be knockdown from received dmg.. so u don't need skills with knockdown effect

 

Okay, it works now, thank you very much.