Is the light bleeding a woman saw nine days into Ramadan considered istihada (irregular bleeding), menstruation, or residual postpartum bleeding, and what is incumbent upon her for the day she broke her fast?

The majority of scholars hold that the maximum period of post-natal bleeding (nifas (definition)) is forty days. If a woman becomes pure after 37 days, then the blood that appears two weeks after her purification is menstruation (hayd). The light bleeding that reappeared nine days after her purification and the completion of her waiting period (iddah (definition)) is also menstruation, and it is to be combined with the first menstruation, as long as the total duration of blood and purity does not exceed fifteen days. However, if the light bleeding occurs after fifteen days have passed from the beginning of the previous menstruation, or if the total of the two bleeding periods combined with the purity between them exceeds fifteen days, then it is irregular bleeding (istihada). The woman must make up for the day she missed fasting after the completion of Ramadan (definition).