Musannaf Ibn Abi Shayba 3:5353

'Affan narrated to us, he said: Hammam narrated to us, he said: Yahya ibn Abi Kathir narrated to us that a man from the people of Ash-Sham narrated to him, who is called Abu Sufyan, that Buhayr ibn Raysan narrated to him that he was with 'Ubadah ibn as-Samit. He witnessed that he (Ubadah) forbade them from praying when the Imam would depart (for a break) during Ramadan. He kept forbidding them, but they did not care and did not desist. So he struck them, and I saw him striking them for that.