Sunan an Nasai
1177
Sahih+2

It was narrated from Ibn Buhainah that:The Prophet (ﷺ) prayed, then he stood up after two rak'ahs while he was supposed to sit, and he continued his prayer. Then at the end of his prayer, he performed two prostrations before the Salam, then he said the Salam

SahihAbu Ghuddah
SahihAl-Albani