Hi I am having same problems. I have this page where I want full width (edge to edge) banner , in cornerstone it displays ok but when I publish image is pushed to left on only show 2/3 of the screen..
I’ve set up page as following:
Template: No Container, header only
Row setting for the image – column container off, marginless columns off
Image is 2546 × 910 saved as jpg
Here is the link of the page
http://www.vitfit.com.au/six-week-body-transformation-2/
Can you help please?