I use PD4ML 3.8.5fx6 to convert html to pdf and have the problem that depending on font size within the paragraph of the footer the footer is not shown. Instead there seems to be a very large margin at the bottom when pdf is viewed in LibreOffice Draw. (Of course I do not use that as my normal pdf viewer. In Adobe Reader the footer is missing as well.)
With a small and large font size it works, but not with a medium one.
The font size (and the timestamp of course) is the only thing that differs between the htmls to be converted.