What is the ruling regarding the fasting of a wife who purified herself from her menstrual period on the second day of Ramadan, then saw blood again on the eighth day?

If the wife has a known habit, and the habit ends with purity, then blood appears after less than thirteen days (the shortest period of purity between two menstruations), this blood is not considered menstruation, but rather istihadah (non-menstrual vaginal bleeding), and she must pray and fast, and there is no make-up (qada') for her.