Their imam does not pray Maghrib in the mosque, so that he can eat iftar at home!
Question

                In our neighbourhood the imam does not pray Maghrib because he goes to break his fast. What is the ruling – are we sinning? Or should we pray Maghrib at home and will that count as prayer in congregation for us?.
Praise be to Allah.Firstly: 
The Muslim 
    must fear Allaah and offer the five daily prayers in congregation in the 
    mosque, unless he is excused because of sleeping, sickness and so on. 
See question 
    no. 8918. 
With regard 
    to Maghrib prayer in Ramadaan in particular, there is a great of neglect 
    concerning it among many worshippers. The imam should be at the head of the 
    worshippers in this prayer for a reason other than the fact that he is 
    obliged to pray in congregation; this reason is fulfilment of the trust to 
    which he has been appointed, or the task with which he has been entrusted. 
If this imam 
    neglects to pray Maghrib in congregation in the mosque, this does not mean 
    that you are sinning or that it is permissible for you to pray at home; 
    rather you must offer the prayer in congregation in the mosque, even if the 
    imam is not present. Each person is accountable for his own deeds. Even if 
    he does wrong, you are still obliged to do the right thing and avoid doing 
    wrong, so as to preserve this ritual which is one of the pillars of Islam. 
It was 
    narrated that ‘Abd-Allaah ibn Mas’ood (may Allaah be pleased with him) said: 
    Whoever would like to meet Allaah, may He be exalted, tomorrow as a Muslim, 
    let him regularly offer these prayers where the call to prayer is given, for 
    Allaah has prescribed the Sunnahs of guidance to your Prophet (S) and they 
    (the prayers) are among the Sunnahs of guidance. If you pray in your houses 
    like this one who stays away from the mosque prays in his house, you will 
    have forsaken the Sunnah of your Prophet, and if you forsake the Sunnah of 
    your Prophet you will go astray. There is no man who purifies himself and 
    purifies himself well, then he goes to one of these mosques, but Allaah will 
    record one good deed for him for every step he takes, and will raise him in 
    status one degree thereby, and will erase one bad deed thereby. I remember 
    when no one would stay away but a hypocrite whose hypocrisy was known, and a 
    man would come staggering between two others in order to stand in the row. 
    Narrated by Muslim (654) 
Imam 
    al-Shaafa’i (may Allaah have mercy on him) said: 
There is no 
    concession allowing the one who is able to pray in congregation not to do so 
    unless he has an excuse. 
Al-Umm 
    (1/277). 
Ibn 
    al-Qayyim (may Allaah have mercy on him) said: 
Whoever 
    studies the Sunnah properly will realize that offering the prayers in the 
    mosque is an individual obligation unless there is an excuse which allows an 
    individual to miss Jumu’ah prayer and prayer in congregation.   
Then Ibn 
    al-Qayyim said: 
What we 
    believe to be the correct view is that it is not permissible for anyone to 
    stay away from praying in congregation in the mosque except one who is 
    excused. 
Kitaab 
    al-Salaah (p. 166)
 Thirdly: 
The way of 
    the Prophet  (peace and blessings of Allaah be upon him) is the best of 
    ways. He would break his fast with fresh dates; if none were available, with 
    dry dates, and if he could not find any dates, he would break his fast with 
    water, then he would go and pray Maghrib. 
It was 
    narrated that Anas ibn Maalik (may Allaah be pleased with him) said: The 
    Prophet  (peace and blessings of Allaah be upon him) would break his 
    fast with fresh dates before praying. If there were no fresh dates, he would 
    eat a few dried dates. If there were no dried dates, he would drink a few 
    sips of water. Narrated by al-Tirmidhi (632); classed as saheeh by 
    al-Albaani in Saheeh al-Tirmidhi. 
What this 
    imam is doing is contrary to the way of the Prophet  (peace and 
    blessings of Allaah be upon him), so you should advise him to come back to 
    the right path. 
And Allaah 
    knows best.