The Prophet ﷺ only prayed the two units after Asr because some wealth had been brought to him which distracted him from praying the two units after Dhuhr, so he prayed them after Asr and never repeated this afterward.
حدثنا قتيبة حدثنا جرير عن عطاء بن السائب عن سعيد بن جبير
إنما صلى النبي ﷺ الركعتين بعد العصر لأنه أتاه مال فشغله عن الركعتين بعد الظهر فصلاهما بعد العصر ثم لم يعد لهما
[Its isnad is daif]Ibn Hibban also recorded it in al-Ihsan (1573) through the same narration from Ata bin Saaib, who became confused in his later years, and he did not narrate this before his confusion set in.On this subject there are also narrations from Ayesha [Bukhari, no. 593, and Muslim, no. 835], from Umm Salama [Bukhari, as a suspended report before no. 590, and Nasai, nos. 581 and 580], from Maymuna [Ahmad 6/333, 334], and from Abu Musa [Ahmad 4/416]."He prayed two rakahs after Asr," recorded by Bukhari, no. 593. And the hadith of Zayd. And from Ayesha, "he never failed to pray two rakahs," recorded by Bukhari, no. 593. And from Umm Salama, mentioned previously at 183.