What is the ruling on praying behind an imam who does not recite aloud in the loud prayers, and who says “Allahu Akbar” when rising from bowing?

Question:
What is the ruling on one who leads people in the loud prayers but does not recite aloud, meaning he prayed with them quietly? Then, when rising from bowing, he did not say “May Allah hear the one who praises Him,” but rather he said “Allahu Akbar,” and he continued the prayer, doing this in all the rak'ahs. What is required of the ma'mums, and what is upon the imam given the situation described? May Allah reward you with good.

Answer:
As for his leaving off the loud recitation, it is leaving off a recommended practice (sunnah) that does not harm or affect the prayer, praise be to Allah; because loud recitation in the night prayer is a recommended practice (sunnah), and quiet recitation is permissible, even though it is better and more preferable to recite loudly and let the ma'mums hear the Qur'an. As for his leaving off “May Allah hear the one who praises Him,” this is leaving off an obligatory act. If he did it intentionally, his prayer is not valid. If he did it out of forgetfulness or ignorance, it is corrected by the prostration for forgetfulness (sujud al-sahw), where he prostrates two times for forgetfulness before the closing salam. Yes.