Ruling on a woman who experiences menstruation after sunset in Ramadan

This is a message from a confused woman (H. M.), who says: A woman fasted in Ramadan, and when one of the days of Ramadan came and Maghrib arrived and the mu'adhdhin called the adhan, she broke her fast. After that, she went to perform wudu' for prayer, but she found that her monthly period had started. Is her fast valid or not?
Answer: If the blood occurs after the sun has set, then the fast is valid. If she did not know of the presence of the blood until after the sun had set, then the fast for that day is valid. However, if the blood came to her before the sun set and she was certain of that, then this fast is not valid; rather, she must make it up. It is necessary to know this.
If the blood came to her after sunset, her fast is valid, or if she did not know of it until after sunset, her fast is valid. If she did not know that it occurred during the day and only became certain of it at night, her fast is valid. However, if she knew that the blood affected her before the sun set and that something came out of her before the sun set, then this fast, in which the blood came out before the sun set, is not valid, and she must make it up after Ramadan. Yes.
The presenter: In a case like this, the woman did not know until after she went to perform wudu' after breaking her fast.
The Shaykh: Yes.
The presenter: Then, if Allah wills, she does not have to make it up.
The Shaykh: Her fast is valid.
The presenter: Her fast is valid.
The Shaykh: Yes.
The presenter: Thank you, His Eminence Shaykh Abd al-Aziz.