Never heard of it. Do provide a link, please.
They were living in rural isolation in India, keeping the laws of family purity, praying three times a day, having a Cohen offer the Passover sacrifice of a lamb on an altar, and observing many other of the minutiae of Jewish religious life, and with a history of their exile 2,700 years ago.
Even so, they and the Ethiopians were required to convert before becoming citizens. That is SOP for highly isolated, though ancient, communities, and actually is a favor, so that the tangled question of mamzerut (children born to adulterous relationships, such as where a divorce was not really valid, but the spouse remarried anyway) is completely preempted.
But before becoming Pentecostalist they were headhunters, animists.