"The Prophet only performed the two rak'ah (units of prayer) after Asr because some wealth came to him which distracted him from the two rak'ah after Zuhr, so he prayed them after Asr, then he did not repeat that."  

إِنَّمَا صَلَّى النَّبِيُّ ﷺ الرَّكْعَتَيْنِ بَعْدَ الْعَصْرِ لأَنَّهُ أَتَاهُ مَالٌ فَشَغَلَهُ عَنِ الرَّكْعَتَيْنِ بَعْدَ الظُّهْرِ فَصَلاَّهُمَا بَعْدَ الْعَصْرِ ثُمَّ لَمْ يَعُدْ لَهُمَا وَفِي الْبَابِ عَنْ عَائِشَةَ وَأُمِّ سَلَمَةَ وَمَيْمُونَةَ وَأَبِي مُوسَى