Al-Dāraqutnī said, “He was not reliable.”
I add: He died in Shawwāl of the year 283 AH, at the age of eighty.
His book al-Dībāj contains a number of objectionable reports.
Al-Ḥākim judged him “weak,” and on another occasion he said, “He was not reliable.”

159 – al-Jabbulī, Abū al-Qāsim Isḥāq ibn Ibrāhīm *

The ḥāfiẓ, Abū al-Qāsim Isḥāq ibn Ibrāhīm ibn al-Jabbulī. Jabbul is a small settlement in the cultivated lands of Iraq.
He heard ḥadith from Manṣūr ibn Abī Muzāḥim and others of his circle.
Abū Sahl ibn Ziyād transmitted from him.
Al-Khaṭīb said, “He was praised for his insight and described as possessing an excellent memory, yet he transmitted only a few reports.” (1)
Ibn al-Munadī said, “He spent most of his life on the eastern side ⦗of Baghdad⦘ (2). White patches (vitiligo) covered his face and body. He would issue legal opinions on the basis of ḥadith and engage in scholarly discussion, but he did not narrate publicly.”
He died in Rabīʿ al-Ākhir of the year 281 AH, at the age of seventy. (3)