Da'eef (weak) hadeeths, Dought & clear, - * Accumulate Voluntary Fasts and Make Them up in Sha‘ban?

How sound is the following hadeeth (narration): "The Messenger of
Allah (peace and blessings of Allah be upon him) used to fast three
days every month, and sometimes he would delay that until a year's
fasts accumulated and he would fast Sha'ban?"
Praise be to Allah
This hadeeth was narrated from the Mother of the Believers, 'Aishah
(may Allah be pleased with her) who said:
The Messenger of Allah (peace and blessings of Allah be upon him) used
to fast three days every month, and sometimes he would delay that
until a year's fasts accumulated and sometimes he would delay it until
he fasted Sha'ban.
This was narrated by at-Tabarani in al-Mu'jam al-Awsat, 2/320. He
said: Ahmad told us: 'Ali ibn Harb al-Jandeesaboori told me: Sulayman
ibn Abi Hawthah told us: 'Amr ibn Abi Qays told us: from Muhammad ibn
'Abd ar-Rahman ibn Abi Layla, from his brother 'Eesa, from his father
'Abd ar-Rahman, from 'Aishah (may Allah be pleased with her) who said.
Then he quoted it, then he said: This hadeeth was not narrated from
'Abd ar-Rahman ibn Abi Layla except via this isnad (chain of
narrators), and 'Amr is the only one who narrated it. End quote.
This is a da'eef (weak) isnad because of Muhammad ibn 'Abd ar-Rahman
ibn Abi Layla – the famous faqeeh (jurist) – of whom Imam Ahmad said:
He had a poor memory and his narration of hadeeth was inconsistent.
Shu'bah said: I have never seen anyone with a poorer memory than Ibn
Abi Layla. 'Ali ibn al-Madeeni said: He had a poor memory and his
hadeeth is weak. Hence the scholars classed this hadeeth of his as
da'eef.
Al-Haythami (may Allah have mercy on him) said:
Its isnad includes Muhammad ibn Abi Layla and there are some
reservations concerning him. End quote.
Majma' az-Zawaid, 3/195
Al-Hafiz Ibn Hajar (may Allah have mercy on him) said:
Ibn Abi Layla is da'eef. The hadeeth of the door and the one that
follows it are indicative of the weakness of what he narrated. End
quote.
Fath al-Bari, 4/252
Ash-Shawkani (may Allah have mercy on him) said:
Its isnad includes Ibn Abi Layla, who is da'eef. End quote.
Nayl al-Awtar, 4/332
The scholars differed concerning the reason why the Prophet (peace and
blessings of Allah be upon him) fasted most of Sha'ban and there are
many opinions, including the one mentioned above, but the evidence for
it is not sound. Perhaps the first one who narrated it was Ibn Battal
in his commentary on Saheeh al-Bukhari (4/115). He also mentioned
other opinions that were narrated by al-Hafiz Ibn Hajar (may Allah
have mercy on him) and added to them, then he said:
More appropriate than this is what is mentioned in a hadeeth that is
sounder than what has been mentioned above. It was narrated by
an-Nasai and Abu Dawood, and classed as saheeh (authentic) by Ibn
Khuzaymah, from Usamah ibn Zayd (may Allah be pleased with him) who
said: I said: O Messenger of Allah, I have not seen you fasting in any
month more than you do in Sha'ban. He said: "That is a month that
people are heedless of, between Rajab and Ramadan, but it is a month
in which deeds are taken up to the Lord of the Worlds, and I like my
deeds to be taken up when I am fasting."
End quote from Fath al-Bari, 4/215
And Allah knows best.