The linked document uses the after pseudo selector to write the href at the end of an a tag and title at the end of an acronym tag when printed. When printed with safari the href printed is often from the wrong a tag. The document XHTML & CSS validate at w3.org and print as expected in opera.
I can reproduce this problem with shipping Safari, but WebKit nightlies do not appear to have it. To test the new behavior, you can download a nightly build from <http://nightly.webkit.org>.
Yeah this was fixed a while back.