Imam Hanzalah al-Sadusi (may Allah have mercy on him) narrates from Sayyiduna Abdullah bin al-Harith (may Allah be pleased with them both), and Sayyiduna Mu'awiyah (may Allah be pleased with him) was his maternal uncle, who said: I was with Sayyiduna Mu'awiyah (may Allah be pleased with him) after the Asr prayer, and he saw some people praying two rak'ahs after it. He said: "What is this prayer? We prayed with the Messenger of Allah (peace and blessings be upon him), and we never saw anyone pray it."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 16809