Freeze breaks the Blood Priest/Preistess boss

If you freeze the priest while he is stealing life from the priestess it wont stop until the freeze ends even if it should of stopped before. The heal is supposed to be like 20-25% of the priests health but when I froze them he just kept healing and healed like 80% total. It will even keep doing damage to the priestess if she is still alive, I had this kill the priestess even though she was ~60% health when the priest started sucking.

Bonus: I'm not sure if this is a bug related to the freeze build up but after killing them both and summoning the respective npc Zolin the priest started attacking me again even though he should've surrendered. He was at 0% hp and unkillable. This might've happened because I killed him while he was frozen?