IS DUA AFTER NAMAAZ WITH IMAM COLLECTIVELY WRONG ?
BECAUSE I KNOW IT IS SUNNAT TO DO IT AFTER NAMAAZ BUT I HEARD IT IS BIDAH WITH THE IMAAM.

Narrated by Busr bin Said (r.a):*
*that Zaid bin Khalid (r.a) sent him to Abi Juhaim(r.a) to ask him what he had heard from Allah's Apostle about a person passing in front of another
person who was praying. Abu Juhaim (r.a)replied, "Allah's Apostle said, 'If the person who passes in front of another person in prayer knew the
magnitude of his sin he would prefer to wait for 40 (days, months or years) rather than to pass in front of him." Abu An-Nadr (r.a) said, "I do not
remember exactly whether he said 40 days, months or years." *

Zaid bin Thabit (May Allah be pleased with him) reported: The Prophet, salAllaahu alayhi wasallam said, “O people! perform your (voluntary) Salat (prayers) in your homes because the best Salat of a man is the one he performs at home, except the obligatory Salat.” [Al-Bukhari and Muslim].

Rasoolullah (Sallaahu-alayhi-wasallam) is reported as saying that any du’a, which is begun with, is not rejected. Because of saying “Bismillaahir rahmaanir raheem” the scales of my Ummah will become heavy on the Day of Qiyaamah. The other people will enquire: "Why is the virtues of the Ummate Muhammadiyyah so heavy?" Their prophets will say: "In the utterances of the Ummate Muhammadiyyah there is such an honourable name of Allah that if it is placed on the one side of the scale, and the sins of the entire creation is put onto the other side then the side with the virtue will be heavier.