Ali bin Abu Talib reported,
The Messenger of Allah ﷺ used to pray two units of prayer after every obligatory prayer except Fajr and Asr.
Azami 2497
Sahihعن علي قال
كان رسول الله ﷺ يصلي على إثر كل صلاة مكتوبة ركعتين إلا الفجر والعصر.
Ibn Khuzayma (1196) narrated it, saying, Bundar told us, Abdul-Rahman told us, Sufyan told us. Another chain, Muhammad bin Ala bin Kurayb told us, Abu Khalid Ahmar told us, Sufyan told us. Another chain, Salm bin Junada told us, Waki told us, from Sufyan, from Abu Ishaq, from Asim bin Damra, from Ali, and he mentioned the same.Ibn Khuzayma said, This is the wording of Waki's hadith. Diya Maqdisi also included it in Al-Mukhtara (521), citing it from Ibn Khuzayma.I say, the apparent meaning of this hadith contradicts what will come later from Ali 
. Bayhaqi pointed out this contradiction.