I never saw the Prophet ﷺ pray a prayer outside its proper time except for two prayers. He combined Maghrib and Isha, and he prayed Fajr before its usual time.In another narration, that was at Jam, meaning Muzdalifa.
ما رأيت النبي ﷺ صلى صلاة لغير ميقاتها، إلا صلاتين جمع بين المغرب والعشاء، وصلى الفجر قبل ميقاتها. وفي رواية: وذلك بجمع- أي المزدلفة.
Bukhari narrated it in Hajj (1682), and Muslim narrated it in Hajj (1289), both through Amash, who said, "Umara narrated to me, from Abdul-Rahman bin Yazid, from Abdullah bin Masud," and he mentioned it. The second narration was mentioned by Muslim.Shawkani said in Nayl (2/491), "Ibn Masud denied combining prayers absolutely, and restricted it to the combining at Muzdalifa, even though he is among those who narrated the hadith of combining at Madinah, as mentioned earlier. This indicates that the combining that took place at Madinah was only apparent, for if it had been a real combining, his two reports would have contradicted each other, and reconciling the two reports whenever possible is what is required."I say, this contains the following observations.First, the hadith of Ibn Masud about combining prayers at Madinah is daif. Tabarani narrated it in Awsat, also called Majma al-Bahrayn (938), from Ali, Husayn bin Maysara Razi narrated to us, Abdullah bin Abdul-Quddus narrated to us, from Amash, from Abdul-Rahman bin Tharwan, from Zazan, from Abdullah bin Masud, who said, "The Messenger of Allah ﷺ combined the first prayer and Asr, and Maghrib and Isha." He was asked about that, so he said, "I did this so that my nation would not be burdened."Tabarani said, "No one narrated it from Amash except Abdullah, and no one narrated it from him except Husayn." Ahmad bin Hatim corroborated him, and through his route it was narrated in Kabir (10/269), "Abdullah bin Abdul-Quddus narrated to us," with the same wording, and he mentioned it.Haythami said in Majma (2/161), "It contains Abdullah bin Abdul-Quddus, whom Ibn Main and Nasai declared daif, while Ibn Hibban deemed him trustworthy. Bukhari said, 'He is truthful, but he narrates from weak people.' I say, he narrated this from Amash, who is trustworthy." End of quote.I say, Abu Dawud and Daraqutni also declared him daif. Abdullah bin Ahmad said, "I asked Ibn Main about him, and he said, 'He is worthless, a wicked Rafidi.'" So someone like him, no attention should be paid to his hadith. As for the statement of Hafiz in Taqrib, "He is truthful but was accused of Rafidism, and he also used to err," it would be more fitting to describe him with the word daif.Second, Ibn Masud's denial of the combining does not indicate that it did not occur, and Abu Hurairah testified to it.Third, interpreting it as a formal combining involves hardship and difficulty, whereas the Prophet ﷺ intended to remove hardship from his nation. And Allah, the Most High, knows best.As for the rest of the hadiths on the prayer at Muzdalifa, see the book of Hajj.