It was recorded by al-Bukhari (3268, 5763, 5765, 5766, and 6391), Muslim (7/14), Ibn Abi Shaybah (8/30/3570), and—through him—Ibn Majah (3590, al-A'zami edition); Ahmad (6/50, 57, 63, and 96); al-Humaydi (259); Ibn Sa'd (2/196); Abu Ya'la (3/194); and al-Bayhaqi (2/2/157/2), through several chains from Hisham, with this report. The addition concerning six months, mentioned in the hadith under discussion, occurs in one narration recorded by Ahmad; its chain is authentic, and al-Hafiz declared it authentic in Fath al-Bari (10/226).
In sum, al-Arzami's narration and the additions it contains are very rejected, except for those portions that concur with Hisham's hadith from 'Urwah and with the hadith under discussion. This includes the revelation of the Mu'awwidhatayn (the two refuge-seeking surahs). Al-Rafi'i mentioned this in his book, and al-Hafiz said in his Talkhis (4/40): “Al-Tha'labi mentioned this in his exegesis as a suspended report from Ibn 'Abbas, and also as a suspended report from 'A'ishah. 'A'ishah's chain is authentic. Sufyan ibn 'Uyaynah recorded it in his exegesis, in Abu 'Ubayd Allah's transmission from him, from Hisham ibn 'Urwah, from his father, from 'A'ishah”—then he cited the hadith—“and it states that the verse, ‘Say: I seek refuge in the Lord of daybreak,’ was revealed.”
This is an important observation from al-Hafiz—may Allah Most High have mercy on him—which does not occur in his book Fath al-Bari, and it is strong supporting evidence for the hadith under discussion. And Allah knows best.
It is useful to mention that some innovators, both in the past and in the present, have rejected this authentic hadith on the basis of specious arguments weaker than a spider's web. Scholars have refuted them in their commentaries, so whoever wishes may consult them. The annotator of Dala'il made a grave error in attributing al-Bayhaqi's narration to al-Bukhari, Muslim, and others, without drawing attention to the rejected elements in it that contradict their narrations!