I know healing + undead = bad, but in the context of both the story and the dialogue for this it makes no sense at all.
When you are playing as Fane and you first hear Lady Amadia tell you to come to her healing mist it causes you to take damage.
Then when you get to the Sanctuary of Amadia and talk with the statue she again tells you (Fane specifically) to step into her healing waters, etc.
Of course, just like before this will cause you to take damage and potentially die.
IMO these instances of the Goddess "healing/helping" you should not count as a normal healing against Fane, since it's meant to be a gift from her to HELP you it makes 0 sense that she'd bless you with something that would actually harm you.