Is the prayer of the congregants invalidated if they precede the imam in prostrating after he rises from bowing and says "Allahu Akbar" instead of "Sami'a Allahu liman hamidah," and then one of them performs the prostration of forgetfulness after the taslim while the others do not?

The most cautious approach for these three is to repeat their prayer because, according to some scholars, the prayer of anyone who deliberately or inadvertently precedes their Imam to prostration is invalidated unless they return to perform it after their Imam. Others, however, consider the prayer of one who inadvertently precedes their Imam to be valid. There is no prostration of forgetfulness (sujood as-sahw) for a congregant if they make a mistake without their Imam. If they prostrated before the Imam, knowing that he had not yet prostrated, their prayer is void and must be repeated. If they prostrated inadvertently, believing that the Imam had already prostrated, their prayer is valid, but the most cautious approach is to repeat it.