I started a Normal Dalaran Heist run sometime before the Rise of the Mech patch, and had paused it just before fighting… Aki? The draenei paladin who buffs all minions in his hand. When I logged into the game today and defeated him, the Heist deck flipped to the last boss, but it was Kizi, the barber; only she showed up with 70 health. Once I started the duel, it went back to Madam Goya, as it should have been. My best guess is that something in the way patches are being deployed makes a saved run reset its deck, at least visually.
This is a known issue, as stated here: