Sometimes the missions are active,other times proactive.If it doesnt say complete u may have to ascend another champion.My opinion amyhow.Sorry im fairly new to game but the missions seem to have gone this way 

I believe I've seen somewhere posted that this quest isn't retroactive and it's intended to be that way, so you'll have to get another 6 star up and running to complete the quest. Frustrating, but at least it's another 6 star, and with Faction Wars on the way, it will come in handy.

I can verify that you need to ascend another hero, in fact one for each affinity. The mission is pretty clear so try preparing for missions in advance.