"You people pray a prayer that we never saw the Messenger of Allah ﷺ perform, even though we accompanied him. He even forbade it," meaning the two rakahs after Asr.
إنكم لتصلون صلاة، لقد صحبنا رسول الله ﷺ فما رأيناه يصليها. ولقد نهى عنها، يعني: الركعتين بعد العصر.
Bukhari narrated it in the Book of Prayer Times (587), from Muhammad bin Aban, who said, Ghundar narrated to us, who said, Shubah narrated to us, from Abu Tayah, who said, I heard Humran bin Aban narrating from Muawiya, and he mentioned the hadith. Abu Tayah is Yazid bin Humayd Dubi.