Does the saying of "Amen" by the congregants before the Imam at the end of Al-Fatiha invalidate the prayer due to precedence?

Saying "Ameen" after reciting Al-Fatiha is a Sunnah for both the Imam and the congregant, according to the majority of scholars. It is desirable for the congregant's "Ameen" to coincide with the Imam's "Ameen," based on the Prophet's (peace be upon him) saying: "When the Imam says 'Ameen,' then say 'Ameen,' for whoever's 'Ameen' coincides with the 'Ameen' of the angels, his past sins will be forgiven."

If the congregant does not hear the Imam's "Ameen," then he should say "Ameen" upon completing Al-Fatiha. The coinciding of the congregant with the Imam in saying "Ameen" after Al-Fatiha is an exception to the disliked act of preceding the Imam, because it is commanded. As for the congregant preceding the Imam in saying "Ameen," it does no harm and earns reward, except for the opening Takbir and the Taslim, which must be performed after the Imam.