Might be you got flat ATK gloves instead of ATK% ones?

Yes. OP, if you could, please share screenshots of the mission and the piece you got. We'll see if we can figure it out. :D

isn't this starting to become a little complicated? I just won two consecutive chestplate with atk blah blah and...the quest mission didn;t flag as completed. 

this is the third time I won that artifact. I nornally sell 1/2 star artfacts to prevent the bank completely filling

This is a Flat Attack artifact. To complete this mission you'll need to win an Attack Percent artifact. They will have a % sign instead of just a number.

way too complicated. it gets boring after the 100th time 

To add: the stat should look like this, rather than just ATK with nothing beside it. 

i

edit: it's quite simple, just a bit of a grind sometimes

Throughout the years i dont think anyone has actually given praise to these quests like "ya man plarium really pulled through this time"

When you google these quests all you see is people having problems with them and in general people being annoyed by those.

We completed those nightmares ourselves but we shouldnt be like ya we all did it, so can you after couple hundred runs lol, we should rather be on agreement that these quests should be changed for newcomers.

Change those quests from "Win a chestplate with ATK % as the primary stat from stage 5 of arnac" to "Win a chestplate with ATK %" period. 

I think its a reasonable solution, someone maybe has even better one?