Musannaf Ibn Abi Shayba 3:727

Al-Thaqafi narrated to us, from Yahya bin Sa'id, who said: I mentioned to Al-Qasim that a man from the people of Yemen mentioned to me that the people, when the Imam would finish the obligatory prayer, would say three takbirs or tahlils. Al-Qasim said: By Allah, Ibn al-Zubayr used to disapprove of that.