The Prophet ﷺ set out in the year of Hudaybiyyah with somewhere over a hundred of his companions. When he reached Dhul-Hulayfah, he garlanded the sacrificial animals, marked them, and entered the state of ihram from there.I cannot count how many times I heard this from Sufyan, until I heard him say, "I do not remember the marking and garlanding from Zuhri." So I do not know whether he meant the specific mention of the marking and garlanding, or the entire hadith.
خرج النبي ﷺ عام الحديبية في بضع عشرة ومائة من أصحابه فلما كان بذي الحليفة قلد الهدي وأشعر وأحرم منها. لا أحصي كم سمعته من سفيان حتى سمعته يقول: لا أحفظ من الزهري الإشعار، والتقليد فلا أدري- يعني موضع الإشعار والتقليد أو الحديث كله.
Bukhari related it in the Book of Military Expeditions (4157, 4158) from Ali bin Abdullah, who said, Sufyan narrated to us, from Zuhri, from Urwa, from Marwan and Miswar bin Makhrama, who said, and then he related the account. On the face of it, this appears to be disconnected, since Marwan and Miswar were not present at the event, but they heard it from the companions of the Messenger of Allah ﷺ, as Bukhari related it in the Book of Conditions (2711, 2712) from Yahya bin Bukayr, who said, Layth narrated to us, from Aqeel, from Ibn Shihab, who said, Urwa bin Zubayr informed me that he heard Marwan and Miswar bin Makhrama reporting from the companions of the Messenger of Allah ﷺ, with fuller detail.