The ruling on the one who raises his head from prostration before the imam, thinking that the imam has raised his head, and waits for the imam until he raises his head?

Question:
May Allah reward you, Your Eminence, father. The questioner says: Today, we prayed the 'Asr prayer, and when we were in the last rak'ah and the imam was in prostration, a man entered and said the takbir in a loud voice. The people praying thought that the imam had raised his head from prostration, so most of the people in the mosque raised their heads, while the imam was still in prostration. Then the imam raised his head from prostration. The question is: What is the ruling on the prayer of the ma'mum (those praying behind the imam) in this case?

Answer:
If one does it intentionally and does not return to prostrate and raise his head after the imam, his prayer is invalid. As for the one who did not do it intentionally, his prayer is valid, because the obligatory thing is that he returns to prostration and then raises his head after the imam; that is what is obligatory. But if he did not do this because he was ignorant, his prayer is valid, and he is excused due to ignorance. But if he knew and did it intentionally, his prayer is invalid. Yes.