Hello,
As I see option “Show Page Heading” is enabled on About Us page http://storage5.static.itmages.com/i/16/1216/h_1481904852_7469994_4345820e3c.jpeg .
Disable it.
Header image is added via row settings in Visual Composer editor http://storage8.static.itmages.com/i/16/1216/h_1481905101_4009479_5df79ddfcc.jpeg .
Regards,
Eva Kemp.