Is the prostration of forgetfulness (sujud al-sahw) obligatory if a worshiper makes a mistake in Surah Al-Fatihah, whether the meaning changes or not, given that he remembered the mistake after the salutation (taslim) and did not perform the prostration of forgetfulness, then prayed another prayer, and thereafter performed the prostration of forgetfulness for the first prayer?

An error in Al-Fatihah that alters its meaning cannot be rectified by prostration; rather, it must be corrected immediately. If the worshiper realizes the error and corrects it, their prayer is valid. If the meaning-altering error is not corrected, that particular rak'ah must be repeated. If the worshiper intentionally makes such a meaning-altering error, the prayer becomes void. However, if the meaning-altering error occurs due to forgetfulness or ignorance, and is then corrected, the prostration of forgetfulness (sujood as-sahw) is prescribed for them. According to the relied-upon view of the Shafi'is, the prostration of forgetfulness is performed before the taslim (salutation of peace).