I prayed Maghrib with Ibn Umar as three units and Isha as two. Malik bin Harith asked him, "What kind of prayer is this?"He replied, "I prayed them this way with the Messenger of Allah ﷺ in this very place with a single iqamah."
حدثنا محمد بن كثير حدثنا سفيان عن أبي إسحق
صليت مع ابن عمر المغرب ثلاثا والعشاء ركعتين فقال له مالك بن الحارث ما هذه الصلاة قال صليتهما مع رسول الله ﷺ في هذا المكان بإقامة واحدة
Its chain is daif. Tirmidhi transmitted it in the Hajj chapter, in the section on combining Maghrib and Isha at Muzdalifa, hadith no. 887, from the hadith of Sufyan Thawri, from Abu Ishaq, through him, and he said, "hasan sahih," though he narrated using "an," indicating tadlis. The previous hadith, no. 1927, suffices in its place.