In my report, there is a Table with one group and PageBreak set to After for the group. If the property ColumnHeadersPrintOnEveryPage is with the default value False, in Interactive view there are three pages generated, one for each group, which is correct.

If I set ColumnHeadersPrintOnEveryPage to True, the number of pages increases to four in the Interactive view mode. There is an additional page break introduced in the last group.