I heard 'A'isha (Allah be pleased with her) as saying: I had to complete some of the fasts of Ramadan, but I could not do it but during the month of Sha'ban due to my duties to the Messenger of Allah ﷺ or with the Messenger of Allah ﷺ.  

كَانَ يَكُونُ عَلَىَّ الصَّوْمُ مِنْ رَمَضَانَ فَمَا أَسْتَطِيعُ أَنْ أَقْضِيَهُ إِلاَّ فِي شَعْبَانَ الشُّغُلُ مِنْ رَسُولِ اللَّهِ ﷺ أَوْ بِرَسُولِ اللَّهِ ﷺ  

This hadith is narrated on the authority of Yahya b. Sa'id with the same chain of transmitters but with this variation that he said that ('A'isha did not observe fast but in Sha'ban) out of regard for the Messenger of Allah ﷺ.  

أَنَّهُ قَالَ وَذَلِكَ لِمَكَانِ رَسُولِ اللَّهِ ﷺ  

" Yahya said: I think it was due to the regard for the Messenger of Allah ﷺ."  

أَنَّ ذَلِكَ لِمَكَانِهَا مِنَ النَّبِيِّ ﷺ يَحْيَى يَقُولُهُ  

This hadith is reported on the authority of Yahya with the same chain of transmitters but no mention is made of the duty to the Messenger of Allah ﷺ.  

عَنْ يَحْيَى بِهَذَا الإِسْنَادِ وَلَمْ يَذْكُرَا فِي الْحَدِيثِ الشُّغْلُ بِرَسُولِ اللَّهِ ﷺ  

If one amongst us had to break fasts (of Ramadan due to natural reasons, i. e. menses) during the life of the Messenger of Allah ﷺ she could not find it possible to complete them so long she had been in the presence of Messenger of Allah ﷺ till Sha'ban commenced.  

أَنَّهَا قَالَتْ إِنْ كَانَتْ إِحْدَانَا لَتُفْطِرُ فِي زَمَانِ رَسُولِ اللَّهِ ﷺ فَمَا تَقْدِرُ عَلَى أَنْ تَقْضِيَهُ مَعَ رَسُولِ اللَّهِ ﷺ حَتَّى يَأْتِيَ شَعْبَانُ