Upvote:2
I haven't found a quote about disagreement between Buddhist schools on rebirth, but I found this 1998 lecture by Johannes Bronkhorst entitled "Did the Buddha Believe in Karma and Rebirth?".
Perhaps you're thinking about Pudgalavada.
From the Atman (Buddhism) wikipedia article:
According to Johannes Bronkhorst, it is possible that "original Buddhism did not deny the existence of the soul", even though a firm Buddhist tradition has maintained that the Buddha avoided talking about the soul or even denied its existence.
The linked footnote reads:
Johannes Bronkhorst (1993). The Two Traditions of Meditation in Ancient India. Motilal Banarsidass. pp. 99 with footnote 12. ISBN 978-81-208-1114-0.