Is it necessary to make up a day from Ramadan along with expiation if a woman intended to fast while not certain of her purity, then became certain of it after Fajr?

If the discharge the questioner saw before Fajr was yellowish, it is considered menstruation. Since she did not confirm purity until after Fajr, she must make up that day, because the default is the continuation of menstruation. She does not owe expiation for breaking her fast on that day; she only needs to make up the fast due to her uncertainty about achieving purity before Fajr, and the default is that it was not achieved.