It seems like you can't complete certain quests in friendly matches against friends. For example the "play 3 games with x, y, and z class" triggered and completed but not the ones like "play 25 minions" or the new "play 50 cards under 3 cost". Was this intended? I'm fairly certain it worked a few days ago but I've been out of the Hearthstone loop. So I'm not even sure if this is a bug or removed feature.