In my Tower theme, the pages “About Us” and “Portfolio” keep getting repeated across the page. But when I activate another theme, it doesn’t have this problem.
Sorry for the late reply.
There is no problem, you may have tried to import demo data multiple times. Or even if you didn’t just go to Appearance > Menus and remove the repeated items from the currently selected menu.
This appears only when Tower theme is activated because this menu is created from this theme.