Has menstruation ended before 12 days when yellow discharge appeared and the brown color did not return, and is it obligatory to perform ghusl and make up for the prayers in this case, given the inability to recall the beginning of the yellow discharge?

The ruling (fatwa) is that yellowish or brownish discharge (ṣufra and kudra) during the period of menstruation is considered menstruation, but outside of it, it is not considered menstruation unless it is connected to blood. So, if a woman sees blood followed by yellowish or brownish discharge connected to it, it is menstruation. If it stops and she sees the usual vaginal moisture, then ghusl (ritual bath) becomes obligatory. However, if she sees yellowish or brownish discharge after that, then if it is during her customary period, it is menstruation; otherwise, it is not. The customary period is not established by the recurrence of yellowish and brownish discharge, according to the relied-upon opinion of the Hanbalis. If the yellowish discharge is connected to blood after its cessation, it is considered menstruation until dryness (jufūf) or the white discharge (qaṣṣah bayḍāʾ) is seen, and it is not a condition to see a brown color after that. If she sees purity but does not perform ghusl, and what she saw after the cessation of blood was vaginal moisture, not yellowish or brownish discharge, then she must make up the prayers she missed after seeing purity and before performing ghusl, exercising careful estimation if she is unable to determine the exact number with certainty.