Hearthstone players finally sees the latest expansion, March of the Lich King. Community was excited to see a whole pack of content themed around a very famous character and its story. But Blizzard recently disabled the Standard and Class card packs, as there was a serious issue.
The expansion comes with Signature cards, which were supposed to be quite rare. The drop rate is expected to be on par with a Golden Legendary, so it means one Signature card should appear around every 181 packs. But the reality was very different than that. When people started opening their packs, they found multiple Signature cards coming out. There were people who found three or four Signature cards from just one pack, and one Reddit user posted a 5/5 screenshot.
Blizzard noticed this and immediately disabled the packs, inevitably causing some complaints. The update is posted on the forums to keep players informed, and there is not a certain expectation about the fix. Decision about the cards which are already found from those packs is probably a more difficult problem to solve.