Background of Site Not Filling Mobile Devices


So after issues trying to get custom sizing right that was below the default of 1080px, we decided to accept 1080px as the new width for our site. We also disable the breakpoints for mobile and table devices. We are doing desktop only. However, on mobile devices, the background is still acting like we have breakpoints enabled. And the background is not spanning the full width of the mobile device. The other elements are maintaining their width.
Please see the attached image.

Can you help us figure this out? Thanks!