Jeptha's Daughter was registered by B. Miller in 1974, although apparently never introduced. Jephtha's Daughter was registered and introduced by B. Miller in 1986. They are different irises. Why Mrs. Miller chose to introduce one with a slightly different name rather than reassign the name from the earlier iris which wasn't introduced, I couldn't say. She presumably had a good reason, though.
As I mentioned in the other thread, AIS currently includes the hybridizer's full name in the registry, but prior to the 1990's (or so, I'm not sure exactly when it changed) they only included the initial of the hybridizer's first name. Since the Hybridizer field in the Iris Database was filled with information directly from the register, that's how they are displayed.
@dave fixed quite of few of those for us, but not all by any means. If you asked him to change all of the B. Miller entries to Bernice Miller, I'm sure he would. Of course, you'd want to be certain that all of the B. Miller entries are, in fact, Bernice Miller's irises (they probably are, AIS was careful about not using the same abbreviation for different people).