Musnad Abu Ya'la al-Mawsili 115:187

Abu Musa narrated to us, Abu Dawud narrated to us, Shu'bah narrated to us from Qatadah, and Hisham narrated to us from Qatadah from Anas: That the Messenger of Allah (ﷺ) performed Qunut for a month. Shu'bah said: "He was cursing." And Hisham said: "He was supplicating against tribes from the tribes of the Arabs." Then he abandoned it after the bowing (ruku'). This is the statement of Hisham.