Is it obligatory to re-fast a day on which a small amount of red blood appeared after performing ghusl following menstruation and fasting on that day?

The sign of purity from menstruation or postpartum bleeding is one of two signs: dryness (the cloth comes out clean, free of blood) or the white discharge (a white fluid that appears after the cessation of menstruation). If a woman sees either of these two signs, she is deemed pure. If blood reappears before the usual end of the menstrual cycle, this is considered part of the menstrual period, and she must abstain from prayer and fasting. If a woman fasts in this situation, her fast is invalid and she must make it up, then perform ghusl (ritual purification bath) after the second cessation of blood.