Sunan Abi Dawud Book 5, Hadith 42
No one told us that the Prophet (ﷺ) had offered Duha prayer except Umm Hani. She said that the Prophet (ﷺ) had taken bath in her house on the day of the Conquest of Mecca and prayed eight rak'ahs. But no one saw him afterwards praying these rak'ahs.
The Messenger of Allah (ﷺ) prayed on the day of the Conquest (of Mecca) eight rak'ahs saluting after every two rak'ahs.
Abu Dawud said: Ahmad b. Salih said that the Messenger of Allah offered prayer in the forenoon on the day of the Conquest of Mecca, and he narrated something similar. Ibn al-Sarh reported that Umm Hani said: The Messenger of Allah (ﷺ) entered upon me. This version does not mention the prayer in the forenoon.
I asked 'Aishah: Did the Messenger of Allah (ﷺ) pray in the Duha? She replied: No, except when he returned from his journey. I then asked: Did the Messenger of Allah (ﷺ) recite the surahs combining each other? She said: He would do so in the mufassal surahs.