This relates to the Play 50 Corrupt Cards weekly quest.
I had this when the weekly quests launched and it only registers every 3rd or 4th corrupt card I play. I’ve now got the quest again and its the same issue. Takes forever to finish and you could do a game where you play 4 and none or only one gets registered to your quest. (Tried it with corrupt and uncorrupted cards)
Also having this issue, playing corrupted cards does not count towards quest completion. Also cards generated by playing Y’sharj the Defiler are not counting towards quest completion.