Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says: The Prophet (peace and blessings be upon him) gave salam after leading them in three rak'ahs of the Asr prayer, then he went to the house of one of his wives. One of his Companions, who was called Dhu al-Shimalayn, came to him and said: "O Messenger of Allah! Has the prayer been reduced?" The Prophet (peace and blessings be upon him) asked: "What has happened?" He said: "You have prayed three rak'ahs." So the Prophet (peace and blessings be upon him) got up, took him by the hand, went out and came to the people who had prayed behind him, and asked: "Is Dhu al-Yadayn speaking the truth?" The people said: "What has happened?" The Prophet (peace and blessings be upon him) said: "He says that I led three rak'ahs." The people said: "He is speaking the truth; we thought that perhaps you had been given some command regarding this." (The narrator says:) So the Prophet (peace and blessings be upon him) led them in one more rak'ah and then, after the tashahhud, performed the two prostrations of forgetfulness.
Al-Bazzar and al-Tabarani in al-Mu'jam al-Kabir recorded it; its chain contains a narrator, Isma'il bin Aban al-Ghanawi al-Amiri, who is matruk (abandoned).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2916