Mecha'thun Warlock's Deck Error

There’s a issue to Hearthstone game about Mecha’thun Warlock’s deck. The card game cataclysm isn’t working no reason at all… There’s no nerf or any change. When sets Mecha’thun and then it, it’s just doesn’t work anymore. The card description says: “destroy all minions and discard your hand.” But my hand don’t get discard at all, only some cards in random ways, that’s clearly a error… I lost many matches because this so i hope the developers fix it and may reward me too. Thank you, blizzard support!