الجواب حامدا و مصلیا
If the referred Imam stood up for the fourth Raka’ath erroneously after performing the last sitting (Qa’da e Akheera), each person’s Salath would become valid by performing the Sajda e Sahw and repetition is not necessary. If the Imam had not performed the Qa’da e Akheera at the end of the third Raka’ath no one’s Salath would have become valid and it is necessary for all to repeat the Salath.
