What is the ruling on the imam intentionally omitting the recitation of additional Quranic verses after Al-Fatiha in the second Rak'ah of the Maghrib prayer?

Intentionally omitting the recitation after Al-Fatihah in the first and second rak'ahs is reprehensible (makrooh) and is considered abandoning a sunnah according to the majority of scholars. The prostration of forgetfulness (sujood al-sahw) is not prescribed for it, because sujood al-sahw is to rectify forgetfulness, not intentional acts. Therefore, if a sunnah is intentionally abandoned, the prayer is valid, though it is considered a misdeed, and sujood al-sahw does not rectify this misdeed.