Teams that lack maturity and play reckless hockey in the third period usually collapse like this and lose.  Buds must get their aggressive forecheck working again; play Kadri, Komarov and Marner more, in these types of situations. Sit Bozak, JVR and Gardiner (late in the game), and you'll fix this problem.  More aggressive points coverage by wingers, could also divert the shots against and allow them to flush their zone quicker.