These are, of course, cleric mobs and have a true complete heal. Very frustrating to get them down to 30% health only for them to get that CH off and start all over.
The levels of the Siren Templars are a bit off. I had a track-happy druid account and conned them on my track list at 55. They were all 55 or 56, meaning you'd need luck as a paladin with pacify on these big nasties.