I was present with Ibn Zubayr and Ibn Abbas when Ibn Zubayr said to Ibn Abbas, "Do you remember when we went out to meet the Messenger of Allah ﷺ as he was returning from a journey?"He replied, "Yes. He carried me and another boy from Banu Hashim with him, but he left you behind."
حدثنا محمد بن جعفر حدثنا شعبة عن حبيب يعني ابن الشهيد
شهدت ابن الزبير وابن عباس فقال ابن الزبير لابن عباس أتذكر حين استقبلنا رسول الله ﷺ وقد جاء من سفر فقال نعم فحملني وفلانا غلاما من بني هاشم وتركك
Its chain of transmission is sahih. This has already come up in the Musnad of Abdullah bin Jafar, 1742, from Ibn Ulaya, from Habib bin Shahid, from Ibn Abu Mulayka, that the questioner was Ibn Jafar and the one who answered was Ibn Zubayr. There we gave preference to what the narration of Bukhari and one of the two narrations of Ahmad indicate, namely that the one who was left out was Ibn Zubayr, and this narration supports that. So the boy from Banu Hashim is Abdullah bin Jafar.Shubah has a more reliable memory than all these narrators, and he made clear that Ibn Abu Mulayka witnessed both the question and the answer. It appears that Ibn Abu Mulayka witnessed a session of questioning between Ibn Abbas and Ibn Zubayr, and between Ibn Jafar and Ibn Zubayr.See Fath al-Bari, 6:133.