Grading: The hadith is sahih, and the narrators of this chain are acceptable (la ba'sa bihim), but there is disagreement over whether it is "connected" (mawsul) or "mursal" from Ja'far bin Muhammad. Sulayman bin Bilal narrated it connected (and no one narrated it from him except Khalid bin Makhlad al-Qatawani, who is saduq (truthful) but narrates unusual reports), as did Ibn Jurayj (as in the following route) and Sufyan bin Uyaynah (as Ibn Abi Hatim mentioned in "al-Ilal" 425). But others among the hafiz students of Ja'far bin Muhammad differed from them, such as Sufyan al-Thawri, Yahya bin Sa'id al-Qattan, Hafs bin Ghiyath, Hatim bin Isma'il and others. Abu Hatim al-Razi (as his son reported from him in "al-Ilal") judged the connected narration of the hadith through Ja'far bin Muhammad to be a mistake. However, it is authentically established as connected through a route other than this one, as will come.

Reference / Source: Ibn Abi Shaybah (2/252) narrated it from Hafs bin Ghiyath; Musaddad in his "Musnad" (as in Ibn Hajar's "al-Isabah" 1/26) from Yahya bin Sa'id al-Qattan; Abd al-Razzaq (3995) and al-Bayhaqi in "al-Sunan al-Kubra" (21/482) through the route of Sufyan al-Thawri; and al-Khatib in "Muwaddih Awham al-Jam' wa al-Tafriq" (2/183) through the route of Hatim bin Isma'il and the route of Hammad bin Isa al-Juhani. All five of them narrate it from Ja'far bin Muhammad, from his father, as "mursal". In their narration it says that "Ibn al-Qishb" was praying, and al-Qishb is the grandfather of Abd Allah bin Malik bin Buhaynah.

Reference / Source: Something similar was narrated by Ahmad (38/22921), al-Bukhari (663), Muslim (711), Ibn Majah (1153) and al-Nasa'i (941) through the route of Hafs bin Asim bin Umar bin al-Khattab, from Abd Allah bin Malik bin Buhaynah.
Technical note / Defect ('illah): But in this narration it says: "The Prophet (peace and blessings be upon him) passed by a man", thus leaving the person in the story unnamed. It has become clear to us from the narration of Ja'far bin Muhammad from his father, and from the following narration of Muhammad bin Abd al-Rahman bin Thawban, that it was Ibn Buhaynah himself.