Does the prayer of one who precedes his imam in standing upright become invalid, thinking that the imam had said "Allahu Akbar" to move after rising from bowing, then (the worshipper) intended to re-enter the state of ihram and completed his prayer with the imam, and then performed an additional rak'ah after the imam's tasleem?
What you did was incorrect. The default rule is that it is not permissible to interrupt prayer except for a legitimate Shar'i excuse. It would have been sufficient for you to return to the bowing position and then rise from it after your Imam had risen. The prayer you recommenced is valid, and you are not required to repeat it.
Summarized from the full answer at Ftawy · reviewed Sep 2, 2026
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