The Messenger of Allah ﷺ said, "Do not let Bilal's call to prayer keep you from your pre-dawn meal, for there is something wrong with his eyesight."
قال رسول الله ﷺ: لا يمنعنكم أذان بلال من السحور، فإن في بصره شيئا.
Narrated by Ahmad (12428), Abu Yaala (2967), and Bazzar - Kashf Astar (982) - all of them through the route of Muhammad bin Bishr, who said, "Saeed narrated to us, from Qatada, from Anas," and he related it. Its chain is sahih.Saeed is Ibn Abu Aruba, a trustworthy and reliable memorizer, and he was among the most reliable narrators from Qatada, except that he became confused in his later years. However, Muhammad bin Bishr heard from him before this confusion set in.This does not contradict his statement, "When Ibn Umm Maktum calls the adhan, eat and drink, but when Bilal calls the adhan, do not eat or drink," for that applies generally, while at times Bilal would err and call the adhan before Fajr due to a problem with his eyesight, as is mentioned in the hadith of Shayban, that he went early to the masjid and sat by one of the rooms of the Prophet ﷺ. He heard his voice, so he said, "Abu Yahya?" He said, "Yes." He said, "Come in." So he entered, and there was the Prophet ﷺ having his morning meal. He said, "Come, join the meal." He said, "O Messenger of Allah, I intend to fast." He said, "I too intend to fast, but our muadhdhin has a problem with his eyesight, and he called the adhan before Fajr."Narrated by Tabarani in Mujam al-Kabir (7/373). Haythami said in Majma al-Zawaid (3/153), "It contains Qays bin Rabi, whom Shuba and Thawri considered trustworthy, though there is some discussion about him." I say, it also contains his teacher, Ashath bin Sawwar Kindi, who is weaker than him.Ibn Khuzayma (1/211) mentioned another interpretation, saying, "It is possible that Ibn Umm Maktum and Bilal had shifts between them, so when it was Bilal's shift, he would call the adhan while it was still night, and when it was Ibn Umm Maktum's shift, he would call the adhan while it was still night." Perhaps the hadith of Anisa bint Habib points to this.