Grading: It is hasan by virtue of the one before it, while this chain is weak because it is mursal.
Technical note / Defect ('illah): An error occurred in the author's chain here in his saying: "that Muhammad bin 'Abdullah bin al-Husayn told him". The correct form is what came in the narration of Ibn Ishaq's "al-Sirah al-Nabawiyyah" (136), in the narration of Ridwan bin Ahmad al-Saydalani, from Ahmad bin 'Abd al-Jabbar al-'Utaridi, from Ibn Bukayr, where it reads: "Muhammad bin Ja'far bin al-Zubayr or Muhammad bin 'Abd al-Rahman bin 'Abdullah bin al-Husayn al-Tamimi told me that 'Umar bin al-Khattab and Sa'id bin Zayd". That is, Ibn Ishaq was in doubt as to which of these two men told him; it is not that he narrated the report from Muhammad bin Ja'far bin al-Zubayr from Ibn al-Husayn. Ibn 'Asakir narrated this report in "Tarikh Dimashq" (19/ 511) by way of Ridwan bin Ahmad al-Saydalani in the same way. This Ibn al-Husayn is among the teachers of Ibn Ishaq, who narrated more than one report of the Sirah from him.