Does the latecomer's not performing qunut after rising to complete his prayer affect the validity of his prayer, and what is the ruling on the congregant's performing qunut (is it recommended or obligatory)?

Qunut in the Fajr prayer is recommended according to the Shafi'is and Malikis, and there is no difference between a congregant (ma'mum) and others. The Shafi'is hold that a latecomer (masbuq) performs qunut when he stands up to make up the first rak'ah of the Fajr prayer. As for the Malikis, there is a difference of opinion among them, and some have adopted the view that the latecomer does not perform qunut in the make-up rak'ah. The latecomer's omission of qunut does not affect the validity of his prayer.