So this situation happens only a few places where you are using the RevSlider. We will have to inspect the pages when you have the site online to provide a specific css for those pages in order to don’t show any background in those situations.
Would be something like this
.page-id-6575 #header-section.header-4 #header, .page-id-6575 #header-section.header-5 #header {
background-image: none!important;
}
You can grab the page id by inspecting the code and check in the body css classes.
If you can’t make it, we will check this when you have the site online.
This image was taken from our demo site
https://www.dropbox.com/s/ezuap65asqi3wld/body_class.png?dl=0
-Rui