Musannaf Ibn Abi Shayba 9:367

Waki’ narrated to us, from Sufyan, from Abu Farwah, from Abu ‘Amr al-Shaybani, from ‘Abdullah ibn Mas’ud, that he issued a legal opinion regarding a man who married a woman and then divorced her before consummating the marriage with her, or she died while married to him. He said: "There is no harm in him marrying her mother." Then he came to Medina and retracted [his opinion], so he went to them and forbade them [from doing so], and she had already borne children.