On the new BOM website, they've got two versions of the page heading: either "The Bureau of Meteorology" or "The Bureau".
It uses media queries to choose what to show. If the page is at least 48em wide, the short version of the heading is hidden. If the page is 47.9375em or narrower, the long heading is hidden.
So there is a 0.0625em range of page widths where both headings will be shown. At regular text sizes this range might fall between integer pixel widths. At large text sizes, it doesn't.