The quest "Into Thick Air" says "Debuff enemy heroes with movement speed slows for 100/175/250 second. I was DP who slows the enemy movement speed by 5/10/15/20% with her 3rd spell. As you can see here http://imgur.com/Dk72qJW , I have used the spell multiple times, but the quest progression shows 0. Here is the YASP link that shows I actually used the spell https://yasp.co/matches/2371245294/performances