It was narrated from Abu Hurairah that :The Prophet (ﷺ) prostrated after the salam when he was not sure
Hadith No. 1235
Sunan an Nasai
Gradings:
Abu Ghuddah:
Sahih Isnaad
Al-Albani:
Sahih Isnaad
Zubair Ali Zai:
Sahih