Sayyiduna Abu Sa'id (may Allah be pleased with him) says: I will only ever give a sa', because in the time of the Messenger of Allah (peace and blessings be upon him) we used to give only a sa' of dates, barley, cheese or raisins. Sufyan bin Uyaynah (may Allah have mercy on him) says: "or a sa' of flour." No one other than Sufyan mentioned flour; therefore it was objected to, so he abandoned it. Abu Dawud said: This addition is an error (wahm) on the part of Ibn Uyaynah.
Muhammad bin Sirin (may Allah have mercy on him) narrated it from Ibn Abbas (may Allah be pleased with them both) as mursal and also as mawquf, by way of error, but it is not established, because it has been narrated through weak chains.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7725