The imam stood up from the first tashahhud in forgetfulness and began reciting al-Fatihah, then he realized and sat down for the tashahhud. Do we sit with him?

Question:
He says: Honorable Shaykh, if I prayed behind an imam who stood up from the first tashahhud and began reciting al-Fatihah in the third rak'ah, and when he was reminded he sat down for the tashahhud, do I sit with him?

Answer:
Yes, you sit with him. He made a mistake in returning, but you sit with him because this is part of following the imam. The imam was appointed to be followed. However, after the taslim, it becomes clear to him that this was a mistake and that it is disliked. Yes.