Is the prayer of one who says "Our Lord, and to You be praise" before the Imam finishes saying "Allah hears the one who praises Him" valid, taking into consideration that the Imam says it after he has fully stood up?

The Imam says "Sami' Allahu liman hamidah" (Allah hears him who praises Him) while rising from bowing, and "Rabbana wa lakal-hamd" (O our Lord, and to You be all praise) when he stands upright. As for the congregant, he says "Rabbana wa lakal-hamd" after the Imam completes saying "Sami' Allahu liman hamidah." If the congregant says the tahmid before the Imam finishes the tasmi', he has acted contrary to what is most preferable, but his prayer is still valid. This is because the rulings concerning verbal actions in congregational prayer are broader than those concerning physical actions, and it is not disliked for the congregant to precede or coincide with the Imam in verbal actions, other than the takbirat al-ihram and the taslim.