Musannaf Ibn Abi Shayba 22:200

Waki’ narrated to us, he said: Al-A’mash narrated to us, he said: I used to recite to Ibrahim, and when I would pass by a letter (word/reading) that he disapproved of, he would not say to me, "It is not such and such." Rather, he would say, "Alqamah used to recite it such and such."