Musannaf Ibn Abi Shayba 3:2116

Muhammad ibn Fudayl narrated to us, from Bayan, from Qays, who said: Sa’d ibn Malik prayed with his companions. He stood up in the third rak’ah, so the people glorified Allah (said "SubhanAllah") to him, but he did not sit. He also glorified Allah and gestured to them to stand up. So he prayed and performed two prostrations (of forgetfulness).