Is praying the 'Isha' prayer behind an imam who is praying the Maghrib prayer contrary to the hadith: "The imam is appointed to be followed"?

Question:
May Allah reward you. Abu Nasir is with us. Peace be upon you. And upon you, peace. Peace. We are here for the Shaykh (may Allah preserve him). Please go ahead. In his first question, he mentions that the Shaykh stated last week in last week's episode that the one who wants to pray the 'Isha' prayer and joins the Maghrib prayer should wait until the imam completes one rak'ah, and then he has two options: either he says the taslim for himself, or he waits for the imam to say the taslim. Meanwhile, there is an authentic hadith that says: "Only the one who completed the prayer with the imam returns to the imam." This is my first question. Wait, let the Shaykh answer.

Answer:
Yes, in matters other than this one, my brother. This is an exception where he has the choice: if he wishes, he says the taslim for himself, and if he wishes, he remains until he says the taslim with the imam.