The Messenger of Allah ﷺ prayed Maghrib and Isha together at Muzdalifa.
حدثنا روح حدثنا مالك عن ابن شهاب
أن رسول الله ﷺ صلى المغرب والعشاء بالمزدلفة جميعا
Its isnad is sahih, and it is a repeat of 5287. It is also in the Muwatta 1:355, and see 6083.