Column offset will affect all breakpoints. When you set 2 offsets on the desktop, mobile will at the same time move 2 offsets. If you want to maintain a different look of the footer, do not use column offset but use a class instead.
Class on a different breakpoint is independent even though the name is same. If the class is set on the desktop to move 20 margin left, on mobile, it remains as it is.
I was spending too much time moving the columns not knowing the offset affects the mobile.
Hope this sharing can help you guys.