Who is "the grandfather" mentioned in the chain of transmission of Ibn Majah's hadith: "from his father, from his grandfather"?

The grandfather mentioned in the chain of narration is the noble Companion Abdullah ibn Amr ibn al-Aas, may Allah be pleased with them both. This is because Shu'ayb ibn Muhammad ibn Abdullah ibn Amr, when narrating from his father about his grandfather, means Abdullah ibn Amr himself, and not his grandfather Muhammad. This has been explicitly stated in other hadiths. It has been confirmed that Shu'ayb and his father heard from his grandfather Abdullah ibn Amr, which means the narration is not mursal (lacking a direct link to the Prophet).