What prompted the debate about grace in 1938 between Metropolitan Kallistos and Bishop Cyprian?

For those remaining with [breakaway Synodal President] Kallistos of Corinth, there also arose an internal dispute over ecclesiological issues, on the occasion of a visit from the metropolitan of the official Innovationist New Calendarist Church, Augoustinos (Kantiotis) of Florina, for a possible rapprochement in 1983. [emphasis added]

Source: Σύντομη Ἱστορία τῆς Μαρτυρικῆς Ἐκκλησίας τῶν Γνησίων Ὀρθοδόξων Χριστιανῶν Ἑλλάδος καὶ περὶ τῆς Ἀποστολικῆς Διαδοχῆς Αὐτῆς [A Brief History of the Martyric Church of the Genuine Orthodox Christians of Greece and its Apostolic Succession], Holy Synod of the Church of the G.O.C. of Greece (Athens: 2105), p. 100.