“ Where it will fail The script does not handle all cases perfectly; with some works, it will function flawlessly, while for others, it will require frequent manual editing. Here are the things that will cause it to fail:
If the header source page doesn't contain a {{RunningHeader}} template (this occurs frequently, for instance, on the first page of a chapter) , the script will attempt to consult neighboring pages and still populate the page you're on, but it will often fail. ”