The ruling on the prayer of one who did not correct the imam's mispronunciation

Question:
He says: Honorable Shaykh, may Allah grant you success. A man led us in prayer and recited al-Fatihah, where he broke the dāl in "Iyyāka na'bud" (You alone we worship), and he did not respond to our correcting him. So I stood up after the prayer ended and repeated my prayer with a second congregation. Is my action correct? And is the imam required to correct his recitation in this way?

Answer:
As for whether the imam is required to correct his recitation, yes, it is obligatory for him to do so if he is able; it is obligatory for him. As for the validity of the prayer, there is a distinction here. If the mispronunciation changes the meaning, such as if he recited "An'amta 'alayhi" (You bestowed favor upon him) instead of "An'amta 'alaynā" (You bestowed favor upon us), or if he broke the kāf in "Iyyāka" (You alone), such that it becomes "Iyyāka" (You alone) with a different vowel, this changes the meaning. The prayer behind him is not valid. One does not pray behind an imam who makes a mispronunciation that changes the meaning. However, if the mispronunciation does not change the meaning, the prayer is valid. For example, if he said "Al-ḥamdu lillāhi Rabb al-'ālamīn" (Praise be to Allah, Lord of the worlds), and he opened the genitive or declined the nominative, and the meaning does not change with that, there is no harm. "Al-ḥamdu lillāhi Rabb al-'ālamīn," if he said "Rabb al-'ālamīn" with an open vowel, or "Rabb al-'ālamīn," this does not change the meaning, so the prayer is valid. But it should be that only one who perfects the recitation leads the people, yes.