Update: Making of a Godol (Page xx)… a report by R' Velvel Kercerg that Rebbitzen Feigel Zaks, the Chafetz-Chaim's youngest daughter, told him, "Eighty percent of what they tell about [my father] is not true." I cannot help but assume that in order to bring out bluntly the idea that not everything told about R' Yisrael-Meir Kagan, author of Chafetz Chaim, is true, his daughter exaggerated the percentage of untruths.)
Making of a Gadol (Page 409): Furthermore, R' Shlomo Lorincz repeated in the name of R' Simhah Wasserman (son of one of the Chafetz Chaim's major disciples, R' Elchonon Wasserman) that the Chafetz-Chaim was somewhat critical of the Netziv. He disapproved of what the Netziv wrote in his commentary on Humash, HaEmek Davar in the introduction to Sefer Bereishis that the Second Temple was destroyed because "the tzaddiqim and hasidim and those who toiled in Torah study ... were not straight (yeshorim) in their general conduct. Therefore, due to the baseless hatred (sinas chinom) in their hearts, they suspected whomever they saw acting not according to their view in Fear of G-d to be a Sadducee and an epikoros. It was understood that the Netziv intended with his words about the Second Temple to find fault with the bnei Torah of his own generation for delegitimizing the religious maskilim and the Lovers of Zion faithful whose outlook on the needs of the Jewish nation did not conform to their own. Despite his criticism, the Chafetz Chaim asked the Netziv for his haskamah on his sepher Ahavas Chesed which was published eight years later than HaEmek Davar.