Wow this is a weird bug.
Maybe it is just taunting you knowing you are going to lose
EDIT* Just tested in the trainer with holy lights and heavy armors, when the creature gets over 50 attack regardless of HP, it antimatters its own creatures
EDIT 2* Idk if this is intended but while testing this i realized that blessing does not change the "Full HP or Attack" It changes for every other buff in the game. So if you play blessing archangels, and you get hit with cc, you can only heal back up to 7HP