´It was narrated that Ibn 'Abbas said:` "The Prophet (ﷺ) used to pray two rak'ahs of Fajr when he heard the Adhan and he made them brief."
Explanation & Benefits
Hafiz Muhammad Ameen
1783. Commentary: Imam al-Nasa'i rahimahullah's intent is that this hadith is not authentic from Ibn Abbas radi Allahu anhuma; rather, it is narrated from Aisha and Hafsa radi Allahu anha. Since in its chain of narration (isnad) Habib ibn Abi Thabit is a mudallis, and he narrates this report with 'an' (the ambiguous transmission), for this reason there is a strong suspicion that there is some flaw in the chain. Or, with this chain, this hadith does not come from Ibn Abbas radi Allahu anhuma; rather, some other narration comes. (The difference between both explanations should be understood carefully.)
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 1783