View the url http://www.songbirdnest.com/ in Safari. Scroll down and notice that you'll scroll through the whole page, and then start seeing a second copy of the page. Now select something in the first copy, notice that your selection is duplicated in the second copy!
I see this on my machine. Refreshing the page doesn't clear the problem, nor does relaunching. Saved web archives do not present the same problem. Printing to a PDF reloads the display correctly (and saves the PDF correctly), but refreshing the page brings back the problem.
I can't reproduce this on the current page. Could this have been fixed or did the part of the page that was causing it get removed?
The page has long since changed.
Thankfully we have Archive.org:
Does not seem to reproduce on TOT however. Closing as WFM.