Storm-Singed Plunder not showing up?

I've done a bunch of Plunderstorm in past week and earned way over 5k, but haven't got storm-Singed Plunder on any of my characters? checked their mail. Is it because I started playing plunder storm late? only started a week ago when I heard about reward:
https://www.wowhead.com/news/new-plunderstorm-reward-gives-heroic-nerub-ar-palace-gear-369014#news-post-369014