Sunan an Nasai
580
Hasan Sahih+2

It was narrated that Umm Salamah said:"The Messenger of Allah (ﷺ) got distracted and did not pray the two Rak'ahs before 'Asr so he prayed them after 'Asr

Hasan SahihAbu Ghuddah
Hasan SahihAl-Albani