Does the prayer become void if the Imam recites a verse while prostrating for fear of stammering, and must the congregants repeat it if the Imam's prayer becomes void?

Reciting the Quran during bowing (ruku') or prostration (sujood) is prohibited. However, the prayer itself remains valid and is not nullified by this act, according to the majority of scholars. This prohibition is one of discouragement (tanzih), not outright prohibition (tahrim). The prayer of the congregants is also valid. As for acceptance, that is an unseen matter known only to Allah, and jurists discuss the validity of the prayer, not its acceptance.