Zayd ibn Aslam also corroborated him, from ʿIyāḍ ibn ʿAbd Allāh, with some abridgement. It was transmitted by al-Bukhārī (956) and al-Bayhaqī (3/280). I have cited its wording in al-Irwāʾ (3/98/630), and the hadith has a continuation through both routes, which you may find there.

Now, be aware that the addition, “standing on his feet,” despite the soundness of its chain in Ibn Mājah’s narration from Abū Usāmah, from Dāwūd ibn Qays—whose name was Ḥammād ibn Usāmah, and who was a trustworthy and precise narrator—who explicitly stated direct transmission, is further confirmed and indicated by the context of the hadith, as is plainly and unmistakably evident. Moreover, Abū Usāmah was corroborated in this addition. Imām Aḥmad said (3/31): “Wakīʿ narrated to us: Dāwūd ibn Qays narrated to us,” through the same chain, in a highly abridged form, with the wording: “He delivered the sermon standing on his feet.”

Ibn Abī Shaybah also transmitted it in al-Muṣannaf (2/189), through this same chain and in the same abridged form, but with the wording: “He delivered the sermon on the Day of Eid while upon his riding mount.” This is how it appears there: “his riding mount”; and he gave it the chapter heading: “The sermon on the Day of Eid upon a camel”! By Allah, I do not know how this came about, but I do know that many hadith masters were subject to such textual distortion or scribal error. Abū Aḥmad al-ʿAskarī wrote his valuable book, Scribal Errors of Hadith Scholars, on this subject; consult it, and you will be certain that “none is safe from a slip or an error except one whom Allah protects,” as al-ʿAskarī said in the introduction to his book.

Remarkably, this scribal error found its way into other hadith sources that come after al-Muṣannaf by one or more levels, such as Musnad Abī Yaʿlā (2/402/