Sunan an-Nasa'i 576
سنن النسائي#576Sahihأَخْبَرَنَا إِسْمَاعِيلُ بْنُ مَسْعُودٍ، عَنْ خَالِدِ بْنِ الْحَارِثِ، عَنْ شُعْبَةَ، عَنْ أَبِي إِسْحَاقَ، قَالَ سَمِعْتُ مَسْرُوقًا، وَالأَسْوَدَ، قَالاَ نَشْهَدُ عَلَى عَائِشَةَ أَنَّهَا قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا كَانَ عِنْدِي بَعْدَ الْعَصْرِ صَلاَّهُمَا .
It was narrated that Abu Ishaq said:"I heard Masruq and Al-Aswad say: We bear witness that 'Aishah said: 'When the Messenger of Allah (ﷺ) was with me after 'Asr, he would pray them (these two Rak'ahs)
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 6:83