Grading: Its chain is "da'if" because of Isma'il bin Rafi' (the storyteller of the people of Madinah); the majority declared him weak.
Technical note / Defect ('illah): There is inconsistency (idtirab) in this chain: sometimes he narrates it like this, sometimes he inserts an unnamed man of the Ansar between Muhammad bin Abi Ziyad and Muhammad bin Ka'b, and sometimes an unnamed man of the Ansar between Muhammad bin Ka'b and Abu Hurayrah. Here and with al-Tabarani it is "Muhammad bin Ziyad", while the correct form is what others have: "Muhammad bin Yazid bin Abi Ziyad", and he is "majhul al-hal" (of unknown status). Al-Bukhari referred to this report in his biography in "al-Tarikh al-Kabir" 1/ 260, saying: "Isma'il bin Rafi' narrated from him the hadith of the Trumpet as mursal, and it is not authentic."

Reference / Source: This report is a portion of the long "hadith of the Trumpet" which Abu Ya'la narrated in "al-Musnad al-Kabir" (as in Ibn Kathir's "al-Bidayah wa al-Nihayah" 19/ 310) from 'Amr bin al-Dahhak bin Makhlad, and al-Tabarani in "al-Ahadith al-Tiwal" (36) from Ahmad bin al-Hasan al-Nahwi, both of them from Abu 'Asim al-Dahhak bin Makhlad al-Nabil, with this same chain. 'Amr bin al-Dahhak added in it a man of the Ansar between Muhammad bin Ka'b and Abu Hurayrah.

Reference / Source: Ishaq bin Rahawayh narrated it in "al-Musnad" (10), Ibn Abi al-Dunya in "al-Ahwal" (55), al-Tabari in his "Tafsir" 2/ 330 and 23/ 22, and al-Bayhaqi in "al-Ba'th wa al-Nushur" (609), by various routes from Isma'il bin Rafi', with this same chain.

Note / Clarification: We say: none of those who recorded this hadith mentioned in it the reading with the light form, as the author (al-Hakim) did. See the details of this light reading in "Mu'jam al-Qira'at" by Dr. Abd al-Latif al-Khatib 7/ 509-510.
General principle: (جُبُلًا), with two dammahs and the light form, was read among the Seven by Ibn Kathir, Hamzah and al-Kisa'i; Abu 'Amr and Ibn 'Amir read (جُبْلًا) with sukun on the ba'; and Nafi' and 'Asim read (جِبِلًّا) with two kasrahs and a doubled lam. See "al-Sab'ah", p. 542.