Following the Imam in a Prostration He Did Not Perform and Omitting the Bowing

Question:
Honorable Shaykh, may Allah grant you success. He says: Our imam led us in the Fajr prayer reciting Surat al-Alaq, but he did not perform the prostration of recitation at the end of it. When he went into bowing, some of the people praying behind him prostrated, thinking that the imam had prostrated for the recitation. Then it became clear to them afterwards that the imam had not prostrated when he said, "Allah hears the one who praises Him." His question is: Given that they followed the imam and did not bow, what is required of them?

Answer:
No, their prayer is not valid. If they realized it soon, they should come back to their bowing and complete their prayer. If the time has passed and a long duration has elapsed, they must repeat the prayer from the beginning, because bowing is a pillar of the prayer. Yes, it was obligatory for them, when they realized it, to stand up and bow, and to catch up with the imam. Yes.