The ruling on the prayer of one who waits for the imam to bow, and whether we rule their prayer to be invalid?

Question:
May Allah reward you, Your Eminence, father. The questioner says: Some students in some schools, when the imam says the takbir of entering prayer, do not say it with him until he bows. Is their prayer permissible? Knowing that they left off reciting al-Fatihah without an excuse. And should I tell them that your prayer is invalid?

Answer:
It is at risk, but do not tell them that it is invalid. Tell them: I fear, I am afraid that your prayer is invalid because you left off entering with the imam and reciting al-Fatihah. You left that off intentionally, intentionally. So I fear that your prayer is not valid. So beware of this. As for saying that your prayer is invalid, no. Yes.