Unable to progress in the achievement "Blight Widow"

I am currently at 42/80 summoned zombies, using Blightfang.
No matter how many enemy minions i infect and kill to summon more zombies, it always keep showing 42/80 in my progress in the Death Knight section of the achievement tab. What to do?

I have this same bug. I am sitting at 15 of 30 (First stage) and I was unable to progress it. I basically can’t complete the achievement currently. I had just recently gotten Blightfang with a pack and I was excited to complete the achievement. Now I can’t. Bummer. Hopefully, Blizzard fixes this.

Are you sure you are doing game in a valid format like ranked , duels or arena …

Friendly games , practice , etc don’t make achievements progress

I am too sitting on 51/80 zombies and even tho I played andpopped a few zombies last game, the just wont increase