(1) The chain is broken. Abu Dawud (no. 1429, Prayer – “The qunut in the witr”) records it through Shujaʿ b. Mukhlad → Hishaym → Yunus b. ʿUbayd → al-Hasan: “ʿUmar b. al-Khattab assembled the people behind Ubayy b. Kaʿb, who led them in twenty rakʿas; he would only perform qunut in the second half of the month, and in the last ten nights he stayed at home, so the people would ask, ‘Where is Ubayy?’” Ibn Abi Shayba transmits, with a strong but mursal chain, from ʿAbd al-ʿAziz b. Rufaʿiʿ: “Ubayy b. Kaʿb in Madinah used to lead them in twenty rakʿas and end with three rakʿas of witr.” He also relates from Yahya b. Saʿid that “ʿUmar ordered a man to lead them in twenty rakʿas.” ʿAbd al-Razzaq, in his Musannaf (no. 7730), gives a robust isnad through Dawud b. Qays… to al-Saʾib b. Yazid: “ʿUmar gathered the people in Ramadan behind Ubayy b. Kaʿb and behind Tamim al-Dari for twenty-one rakʿas; they recited the long surahs of one hundred verses and finished close to dawn.” Al-Bayhaqi, Sunan, 2/496, cites a sound chain (all narrators upright and reliable) through ʿAli b. al-Jʿad → Ibn Abi Dhiʾb → Yazid b. Khusayfa → al-Saʾib b. Yazid: “In ʿUmar’s time they stood for twenty rakʿas; they recited the long surahs, and in ʿUthman’s time they had to lean on their staffs because of the length of the standing.” (2) Reported by Ahmad 5/126; al-Bukhari (nos. 2426, 2437); Muslim (no. 1723); Abu Dawud (no. 1701); and al-Tirmidhi (no. 1374), all through Shuʿbah → Salamah b. Kuhayl → Suwayd b. Ghafalah: “I went out on campaign with Zayd b. Suhan and Salman b. Rabiʿah and found a whip, which I picked up. They said, ‘Leave it.’ I replied, ‘No; I will announce it. If its owner comes, well and good; otherwise I shall use it.’ On returning from the expedition I performed Hajj and reached Madinah, where I told Ubayy b. Kaʿb what had happened. He said: ‘In the Prophet’s time I found a purse containing one hundred dinars. I brought it to the Messenger of Allah, who told me, “Announce it for a year.” I did so but found no claimant. I returned and he repeated, “Announce it for a year.” After three such years with no claimant he said, “Keep a record of its amount, its container and its tie; if the owner appears give it to him, otherwise make use of it.” I used it thereafter.’ I later met him in Mecca and asked whether it was three years or only one; Shuʿbah (the narrator) was unsure which Suwayd had said.”