I do not know if this is a bug or not, which is why I decided to as in Q and A. Will Zhentarim Fear Speaker stack with healer cleric for more overheal hp?Overhealing: Healers convert excess healing into temporary hit points. The hit point bonus is limited to 5/ Healer level (Harper Priest levels count, too), and lasts for a period of three rounds. A Healer level 13 can overheal for up to 65 points. The duration is refreshed on further applications of Overhealing.
If it is then it does not do so currently, tested it on the PGCC.