This has to be a bug -
1.Create a new project
2.Add a Section with VH 100
3.Add a background image to the section
4.Change the views - Tablet / mobile landscape and portrait show the image
5.On the mobile landscape view - change the image to be hidden
Note that the image is now also hidden on mobile portrait but also Tablet!
This also happens if the mobile image needs to be different - the Tablet view is linked to mobile and not Desktop which is where it should be inherited from.