Is the collective recitation of Surat Al-Samad in a moderate voice at the beginning of every lesson, with the intention of instilling its individual continuation, and the claim that the Prophet (peace be upon him) taught his companions remembrance in this manner, authentically reported from him? And does this contradict Ibn Mas'ud's disapproval of collective remembrance in the mosque?

Gathering for remembrance (dhikr), reading the Quran, and studying the Sunnah (definition) is commendable, provided it does not involve innovations (bid'ah). Reciting Surat Al-Ikhlas (definition) in one voice is an innovation that neither the Prophet, peace and blessings be upon him, nor his companions ever did. The claim that the Prophet taught his companions remembrance in this manner is not supported by any authentic hadith (definition); rather, he taught them individual supplications and remembrances. What these young people are doing by reciting in one voice falls under Ibn Mas'ud's disapproval of communal dhikr.