Musannaf Ibn Abi Shayba 3:2392

Ibn ‘Ulayyah narrated to us, from Ayyub, from Muhammad ibn Sirin, from Kathir ibn Aflah, who said: We arrived at the mosque and I had not yet prayed Maghrib, so the prayer was called, and I prayed with them while I thought it was Maghrib. Then it turned out to be Isha. So I stood up and prayed Maghrib, then I prayed Isha. Then I asked, and they instructed me to do what I had done.