Abu Dawud said: This has been narrated by Ayyub from Nafi' from Ibn 'Umar as a statement of Ibn 'Umar. Ibn 'Umar was never seen combining these two prayers except on the night he was informed about the death of Safiyyah. The tradition narrated by Makhul from Nafi' indicates that he (Nafi') saw Ibn 'Umar doing so once or twice.
In-book : Book 4, Hadith 12
English translation : Book 4, Hadith 1205