(Sayidina) Ibn `Abbas (May Allah be pleased with them both) said, the Prophet ﷺ was the most generous of people, and he ﷺ was most generous in Ramadan when Jibreel (upon him be peace) met him. Jibreel (upon him be peace) used to meet him every night during Ramadan to revise the Qur’an with him ﷺ. When Jibreel (upon him be peace) met him, he ﷺ was more generous than the bountiful wind. (Sahih al-Bukhari, 1902).
The Hadith above is authentic without doubt, since it is a Musnad Hadith from Sahih al-Bukhari. The Hadith alludes to the Prophet ﷺ completing the Quran in Ramadan. It is not explicit regarding the issue, nor is it restricted to a single completion (Khatm).
Imam Ibn Hajr al-Asqalani explained the meaning of comparing the generosity of the Prophet ﷺ to a bountiful wind.
Meaning he ﷺ was swifter than the wind in generosity. And he (Ibn `Abbas May Allah be pleased with them both) used the word Mursalah (bountiful) to allude to the consistency of merciful bestowing, and extensiveness of generous benefit. Just like a bountiful wind encompasses everything it touches. (Imam Ibn Hajr al-Asqalani, Fath al-Bari).
And Allah Most High Knows Best.
-Answered by Shaykh Noorud-deen Rashid (06.04.2022)