Musnad Ahmad 775:17

Abu Abd al-Rahman said: It was in my father’s book: Yazid ibn Harun narrated to us, Fā’id ibn Abd al-Rahman informed us, he said: I heard Abdullah ibn Abi Awfa say: A man came to the Messenger of Allah, peace and blessings of Allah be upon him, and said: "O Messenger of Allah, there is a young man here who is dying, and it is being said to him: 'Say: There is no god but Allah,' but he is unable to say it." He said: "Did he not use to say it during his life?" He said: "Yes." He said: "Then what prevented him from it at the time of his death?" Then he mentioned the hadith in its entirety. My father did not narrate these two hadiths; he struck them out from his book because he was not satisfied with the hadith of Fā’id ibn Abd al-Rahman, and in his view, he was a narrator whose hadith is abandoned.