Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates from the Prophet (peace and blessings be upon him), concerning a person who dies owing fasts of Ramadan that he was unable to make up: "Half a sa' of food should be given to a poor person on his behalf for each day."
This is wrong in two respects: first, that it was narrated as a saying of the Prophet (peace and blessings be upon him) (marfu'), whereas it is the saying of Sayyiduna Abdullah bin Umar (may Allah be pleased with them both); second, that it is half a sa', whereas Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said: one mudd of wheat. Another narration is from Ibn Abi Layla in which there is no mention of the sa'.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8217