I have the same problem, exactly like you said. In my vampire family, one of them died and I kept him as a ghost, he's a ghost-vampire, it works on him instead.
Since vampires are one of my two favourite life states, I have a lot of vampires from multiple houses who all had the move as bat power. Having them all meet and transforming all over the place was far too annoying so I removed the power on every single one of my vampires, always use an umbrella outside, and avoid meeting during the day so none of my uncontrolled vampires die in the sun.
It's a shame the power works the way it does.
