She'll eat them if stressed by you or tankmates. It's a difficult thing to avoid. I'd guess as soon as you see eggs, remove all other salamanders from the enclosure and disturb her as little as possible.
BTW, you often see a lot of info out there about how difficult it is to raise Plethodontid eggs without the mother, but in my single attempt at it I successfully hatched P. albagula eggs without the mother. I just kept them moist on soil. I certainly didn't do anything special for them. You might consider trying to raise them alone.