Some varieties do and others do not.
I know it is not the answer you are looking for but that is about it. I have had several that are fine but I know others who had some that do eat corals. I believe there are several different species out there and they are different. I also think there are others species that look similar and is is case of mistaken identity.
There will be those that claim they do but that is not true only some do.
No.
Ive seen them munch on zoas that were questionable though but they do not actively seek out healthy coral. Youll see them munching on dead things around the corals though.
Likely also not asterina and aquilonastreas that do this as theyre usually misidentified.