Sayyiduna Anas (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) used to recite the qunut after the middle of Ramadan.
Abu Ahmad (Ibn Adi) said: Abu Atikah Tarif bin Salman (also called Ibn Sulayman) is munkar al-hadith (his narrations are rejected); I heard Ibn Hammad mention this from al-Bukhari.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4637