Hmm… Here I can only guess. Of course, PD4ML does not try to logically interpret source documents and recognize date info there.
Obviously the source HTML is generated dynamically. The web resource (JSP, PHP etc), which generates the HTML probably takes care about locale info comes with HTTP request.
PD4ML does not send any locale info, so the page is generated with the locale defaults.
P.S. Sorry for the delay with the reply.