The divorce of a slave woman is two pronouncements and her waiting period is two menstrual cycles

It is narrated from Sayyidah Aishah (may Allah be pleased with her) that the Prophet (peace and blessings be upon him) said: "The divorce of a slave woman is two pronouncements, and her waiting period is two menstrual cycles." Abu Asim said: I mentioned this to Muzahir bin Aslam and said: "Narrate it to me just as you narrated it to Ibn Jurayj," and he narrated it to me in the same way through Sayyidah Aishah.
Muzahir bin Aslam is an elder of the people of Basrah whom none of the eminent hadith scholars has criticised, so this hadith is sahih, but the two Shaykhs did not record it. However, a hadith has been narrated from Ibn Abbas that apparently contradicts it.

It is narrated from Abu Hasan (a freed slave of Banu Nawfal) that he asked Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) for a ruling about a slave who was married to a slave woman; he gave her two divorces, and after that they were both freed: may he now propose marriage to her (again)? He said: "Yes, the Messenger of Allah (peace and blessings be upon him) gave this very judgement."

Hammad bin Zayd said: I asked Ayyub: Do you know of anyone who held the same view as al-Hasan (al-Basri) concerning «amruki bi-yadiki» ("your matter is in your hand"), that it counts as three (divorces)? He said: No, except something that Qatadah narrated to us from Kathir, the freed slave of Abd al-Rahman bin Samurah, from Abu Salamah, from Sayyiduna Abu Hurayrah (may Allah be pleased with him), from the Prophet (peace and blessings be upon him), to the same effect. Ayyub said: When Kathir came to us, I asked him, and he said: "I have never narrated this hadith." I mentioned this to Qatadah, and he said: "Of course (he narrated it), but he has now forgotten."
This is a gharib and sahih hadith from the narration of Ayyub al-Sakhtiyani. In the Book of Marriage, in the chapter "Marriage without a guardian", I have mentioned the names of trustworthy hadith scholars, Companions and Successors, who narrated a hadith and then forgot it.