What is the ruling for a follower of the Shafi'i school to recite the qunut supplication in the morning prayer?

In the Shafi'i school, reciting the qunut supplication after rising from the bowing (ruku') in the final unit of the obligatory morning prayer is among the emphasized Sunnahs. If a follower of the Shafi'i school prays behind a Hanafi imam, they should recite the qunut supplication after rising from ruku' if there is enough time. If there is not enough time to recite it, they may omit the qunut, and according to the stronger opinion in the school, they should perform the prostration of forgetfulness (sujud al-sahw) separately from the imam at the end of the prayer. (Nawawi, al-Majmu‘, 4/290) However, even if they do not perform the prostration of forgetfulness, their prayer is still valid.

Source: T.C. Diyanet İşleri Başkanlığı, Din İşleri Yüksek Kurulu