Cursed Spirit Can't be killed for Achievement Tiny Terrors in Tanaan

[Beastsam]

WoW Freakz link: https://www.wow-freakz.com/quest_helper.php?quest=39162&&name=fel-legendary-pet-tracking-quest-4

Bug description: Cursed Spirit have high speed so It goes first doing skill 2 (Ghostly Bite) doing at list 866 damage + Stun, then Skill 1 ( Fel Corruption)
hitting around 600 damage all the pets. My pets have so low HP left that is impossible to even hit the Cursed spirit below 50%. After cooldown again,
skill 2, then 1 and all pets are dead.
I tried to kill it at list 25 times. I used Mechanical pets, Undead, Critter, Elemental, Flying (to try to hit first), Nothing works.

Proof: https://imgur.com/a/ltPwP9k
https://imgur.com/a/1xDJhhH

Please fix it. Lower the speed, lower the crazy damage, make it to not use skill 1 all the time, just please do something so it will be kilable.
Thanks.

[Barnacle]

These pets are supposed to be extremely hard to kill, try looking up a guide on how to do it.

XXX Barney