what artefact misson is it some ppl miss understand them and put the wrong gear on

Show me some pictures of what mission, and then your gear. I'll see if I can help you figure it out. :)

It's really allways the same. People don't read the missions and say the game is broken.

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now i collected few of them all 3 stars all equipped...help

You're going to need to share more pictures, showing the champs who you think qualify for this.

Keep in mind that we get these kind of questions a LOT and in nearly all cases, people overlooked or misunderstood one  of the requirements. It's rarely the game's fault. 

none  of  the  missions  are  bugged  so  far.  Usually human  error

All i can suggest is look at the gear is it actually % or flat stat 

if it just says atk then thats a flat stat and you need atk%

None of the pics you posted shows you fullfilled the requirements of the quest.

You used attack champs, that is indeed needed to do the quest. You showed us that these attack champs have boots, gloves and chests of the attack set. That is NOT the quest. The set doesn't matter, it could be items from any set.

The quest is to equip items with % atk as mainstat. 

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thank you Skadi , you helped a lot :)