I prayed the Isha prayer at Mina with the Messenger of Allah ﷺ as two rakahs, with Abu Bakr as two rakahs, with Umar
as two rakahs, and with Uthman
as two rakahs during the early part of his caliphate. Then Uthman later prayed it in full, may Allah be pleased with them all.
حدثنا مبشر بن إسماعيل حدثنا الأوزاعي عن الزهري
صليت مع رسول الله ﷺ صلاة العشاء بمنى ركعتين ومع أبي بكر رضي الله عنه ركعتين ومع عمر رضي الله عنه ركعتين ومع عثمان رضي الله عنه ركعتين صدرا من خلافته ثم أتمها بعد عثمان رضي الله عليهم أجمعين
Its isnad is sahih. Mubashshir bin Ismail Kalbi Halabi is trustworthy and one of the teachers of Ahmad. He was deemed trustworthy by Ahmad, Ibn Main, and others. Ibn Saad said in Tabaqat 2/7/173, "He was trustworthy and reliable." The hadith is repeated at 5178, and given at greater length at 5214 and 5240. See also 5757.