That isn’t normal behaviour. If your site is still offline and you want to fix this now, you’ll need to dive into using the browser’s developer tool. Inspect the footer widget and and try to see why the expected rule isn’t taking effect and which rule is taking precedent. The width of each widget should be 100% at that point.
Alternatively, if the site is live, please, send a link. If not and you’d rather not spend time diagnosing, I can take a look when it’s live.