Nachman Horodenker, [Gr. Father of Nachman of Breslev] - אביו של ר' נחמן הורדונקר

Google Translate:
" . . . In the book "Rabbi Nachman of Breslev" by Rabbi Yitzchak Alfasi, he brings on page 18: "The father of his father, Rabbi Nachman was the son of Rabbi Yitzchak of Horonka, the son of Rabbi Yitzchak of Zalkawa (the first Rabbi Yitzchak was born after his father's death and was named after him) ... ",

" . . . Whereas in the tree that appears here on the site appears that Rabbi Yitzchak of Zalkawa is the father of Rabbi Nachman Hordonker and not his grandfather, is this a mistake?