Sacrificial pact or w/e it's called is either bugged entirely as to not work. Or the conditions for it to trigger are so specific that it never triggers. My healer will just watch the tank die with it being available and not use it.
Edit: Think 2nd skills for healer in general might just be broken. My Rogue is sitting at 0 mana and the healer is refusing to use the +50% mana to lowest mana party member ability too.