What is the ruling regarding my prayer behind an Imam who does not emphasize the letter "ya" in "iyyaka na'budu" while believing he does, and is it permissible for me to bow before he completes the recitation of Al-Fatiha if the Imam reads quickly?

The ruling on the prayer of one who recites "iyyaka" without stressing the "ya" in Al-Fatiha and the ruling on following such an imam have been previously clarified. Stressing the "ya" in "iyyaka" does not mean exaggerating it until it approaches the sound of "jeem." If the imam recites the "ya" without lightening it, then his lack of excessive stress does not affect the validity of his prayer or the prayer of those following him. One should not abandon the mosque for this reason. It is permissible to go to another mosque, even though praying in the neighborhood mosque is better unless there is an impediment. As for the congregant's recitation of Al-Fatiha, the preponderant opinion is that it is obligatory. If the imam bows before the congregant completes it, the congregant should complete it unless the imam precedes him by three intended pillars. According to the Maliki and Hanbali schools of thought, following the imam takes precedence over completing Al-Fatiha.