What is the "lahn" (linguistic error/deviation) that Uthman ibn Affan (may Allah be pleased with him) meant by his statement, "I find in it a lahn that the Arabs will rectify with their tongues," after compiling the Qur'an into a single mushaf, and does this contradict the Almighty's saying: "Indeed, it is We who sent down the Dhikr (the Qur'an), and indeed, We will be its Guardian"?

This statement attributed to Uthman (may Allah be pleased with him) is incorrect. Many scholars have denied the authenticity of its attribution to him, including Ibn al-Anbari, Ibn al-Jawzi, al-Zamakhshari, Abu Hayyan, al-Alusi, and Ibn Ashour, who all stated that it is a weak narration with a disturbed and disconnected chain of transmission. It is not befitting of Uthman, who compiled the Mushaf with the participation of the Companions, and whose compilation was unanimously agreed upon to conform to the last عرضة (recitation) of the Qur'an, to see an error in it and leave it as is. How can it be conceivable that he would say such a thing in the presence of the Companions and they not object, when they were the protectors of the religion? Had he seen any flaw in it, he would have corrected it.