I and many other people did not follow the Imaam in a verse of Sujood

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

Scholars hold different opinions regarding the ruling of the prayer of one who does not follow the Imaam in the prostration of recitation. Some of them said that it is still valid because the prostration of recitation is not included in the basic actions that one should follow the Imaam in. Rather, he should follow him due to the rule of following the Imaam. They said that leaving an obligatory action that is not a condition of validity does not entail invalidation. Some other scholars viewed that the prayer of the one who does not follow the Imaam in the prostration of recitation is invalid for the Prophet, sallallaahu ‘alayhi wa sallam, said: “And when he prostrates, then prostrate.” [Al-Bukhari and Muslim] 

Accordingly, there are different opinions regarding the validity of the prayer in question and thus it should be prayed again in order to be on the safe side.

invalidity of the prayer of one who does not follow the Imaam in the prostration of recitation is limited to the case if one does this without any reason or excuse. However, if he does this due to an excuse, then it will not be invalid.

An-Nawawi said: “If the Imaam prostrates while the followers do not know until he raises his head from prostration, then the prayer of the followers will not be invalid because they did not follow him due to the excuse (of not knowing).” [Al-Majmoo‘]