The ruling on the prostration for forgetfulness of the one who joins the prayer late with the imam after the closing salam

If the imam makes a mistake that requires prostration for forgetfulness, and this prostration occurs after the closing salam, does the one praying behind him say the salam with the imam? Then, when the one who joined late stands up to make up the rak'ahs he missed, does he return to prostrate with the imam?
Answer: If the imam prostrates and the one who joined late has not yet stood up, he prostrates with him. As for if it is before the closing salam, he prostrates with him in all cases. As for if it is after the closing salam, if the imam prostrates immediately before the one praying behind him—the one who joined late—stands up, then he prostrates with him. Then, after the imam says the salam, the one who joined late stands up and makes up what is required of him. However, if the one who joined late has already stood up, and then the imam prostrates, he is not required to return. Rather, he completes what is required of him, then prostrates for forgetfulness after making up what is required of him. This is because he is excused when he separates, as he intended to separate and became independent from his imam to make up what is required of him. Thus, his prostration is after the completion of what is required of him. However, if the imam hastens to prostrate as soon as he says the salam, before the one praying behind him stands up, then he prostrates with him, and praise be to Allah, and that is sufficient for him. Yes.
The presenter: May Allah reward you with good.