Musnad Ahmad 626:83

Yazid narrated to us, Mas'udi informed us, from Ziyad ibn 'Alaqah, from al-Mughirah ibn Shu'bah, who said: "The Messenger of Allah (ﷺ) led us in prayer, and he stood up during the two rak'ahs (without sitting for the first tashahhud). We glorified him (by saying 'SubhanAllah'), but he continued. When he completed the prayer, he performed two prostrations of forgetfulness." And he said once: "Those behind him glorified him, so he signaled for them to stand."