The ruling on the prayer of one who omitted the first tashahhud out of ignorance

Question:
An imam prayed the midday prayer with his congregation and did not sit for the first tashahhud. When he realized this, he stood up and performed a complete rak'ah to make up for the first tashahhud he had left out. This is permissible, and he did not know. What is the ruling on his prayer and the prayer of those behind him?

Answer:
This is a mistake, and the correct action for the mistake due to ignorance is that it is obligatory for him to perform two prostrations of forgetfulness, or he does not say the taslim until he performs two prostrations, as the Prophet (peace and blessings be upon him) did when he left out the first prostration and finished his prayer. He said takbir and performed two prostrations before saying the taslim, peace and blessings be upon him. This is what is prescribed. Or he performs a complete rak'ah; there is no need for that. However, for the sake of the ignorant person, the prayer is valid. For this reason, when the Prophet (peace and blessings be upon him) prayed five rak'ahs and was not informed until after the taslim, he did not order those who followed him to repeat the prayer because of their ignorance. He asked them, and they said, "We thought something had happened in the prayer." He said, "If something had happened, I would have informed you, or if I had forgotten, you would have reminded me." He did not order them to repeat it because they performed it out of ignorance and thought that an extra rak'ah had been added to the prayer. Likewise, the companions of Dhi al-Yadayn, when he prayed with them and they followed him out of ignorance, thinking that the prayer had been extended, he did not order them to repeat it. Rather, he completed the rest of the prayer with them and performed the prostration of forgetfulness, and he did not order them to repeat it. The point is that ignorance and forgetfulness are an excuse for not repeating the prayer. Yes.