How valid is the reported occurrence of a prayer resembling Salat al-Tasabih on the last Friday of Ramadan, to be performed after the Friday congregational prayer?

This prayer is a reprehensible innovation (bid'ah munkarah), and the hadith (definition) narrated concerning it is fabricated (mawdu'). It is forbidden to repeat a prayer after its time has elapsed, even in congregation, and similarly within its time without a congregation and without a reason necessitating it. It has become a cause for the general public's laxity in performing obligatory prayers, as they believe that performing it in that manner atones for them.