Is it obligatory to ascertain the imam's knowledge of the rulings of recitation and prayer before following him in congregational prayer?

A Muslim must pray with Muslims in the mosques, and is not obliged to investigate the rulings concerning the imam's recitation and prayer. This is because whoever leads the congregation is usually qualified to lead. However, if a deficiency in the imam's recitation of Al-Fatiha becomes apparent, then one should act accordingly.