Accordingly, everything we have presented confirms the soundness of those scholars who declared the report defective on account of its broken chain. The ḥadith is weak, unfit to be cited as evidence, let alone to be pitted against the rigorously authenticated narrations previously quoted from the two Ṣaḥīḥs and other collections.
Note: I have specified the exact chapter in which Ibn Mājah records this ḥadith in his Sunan—something I do not usually do when listing sources—because I found the aforementioned scholar, in his critical notes, saying:
“In al-Muntaqā, Dhakhāʾir al-Mawārīth, al-Mundhirī as quoted by the commentator on Abū Dāwūd, and Ibn Ḥajar in al-Talkhīṣ, the ḥadith is attributed to Ibn Mājah; indeed, the author of Dhakhāʾir even pin-points it to the Book of Funerals. After an extensive search, however, I was unable to locate it there.”
There is also a narration on the same topic from ʿAmr ibn Shuʿayb, from his father, from his grandfather; it will be cited shortly.
Another report states: “Abū Mūsā related that the Prophet ﷺ was sitting in a place where water lay, having uncovered one—or both—of his knees. When ʿUthmān entered, he covered them.”
Al-Bukhārī, al-Ṭabarānī, and al-Bayhaqī transmitted it through the route of Sulaymān ibn Ḥarb, who said: Ḥammād ibn Zayd narrated to us, saying: ʿAlī ibn al-Ḥakam and ʿĀṣim al-Aḥwal both related that they heard Abū ʿUthmān report it from Abū Mūsā.
There are additional ḥadiths on this subject. Among them is the narration of Abū al-Dardāʾ, who said: “I was sitting with the Prophet ﷺ when Abū Bakr approached, grasping the edge of his garment so that his knee showed. The Prophet ﷺ said, ‘As for your companion…’”