Does sin befall one who takes back his wife after divorcing her while she is menstruating, based on the fatwa of Ibn Taymiyyah, Ibn Baz, and Al-Uthaymeen, knowing that he had previously divorced her while she was menstruating?

If you divorced your wife for the second time during her menstrual period, and you were aware of her menstruation, then you are sinful. The divorce is valid according to the majority of scholars. Based on this, your wife has been divorced twice, and you may take her back as long as her waiting period ('iddah) has not ended. Her waiting period concludes when she becomes pure from her third menstrual period after the divorce, or after three months if she does not menstruate, or upon delivering her child if she is pregnant. Sheikh al-Islam Ibn Taymiyyah disagreed, stating that divorce does not occur in this situation. However, what is closer to piety and caution is the view of the majority, which holds that the divorce of a menstruating woman is valid.