Is Hadith No. 976 in "Al-Adab Al-Mufrad" authentic or weak, and what are the reasons for its weakness if it is weak?

The narration that states "Ali saw Al-Abbas kissing his hand and feet" has a weak and suspended chain of transmission (isnaad). The reason for its weakness is the unknown identity (jahalah) of its narrator, Suhayb, the freed slave of Al-Abbas. Imam Al-Bukhari's book "Al-Adab Al-Mufrad" includes narrations and reports (athar) that vary between authentic (sahih) and weak (da'if), marfu' (traced back to the Prophet) and mawquf (suspended at a Companion), and maqtu' (cut off at a Successor); not everything in it meets the criteria of his Sahih collection.