The RSS ATOM feed from this site seems to list multiple links for articles where I’ve changed the date once it’s published (this normally results from a mistake transferring the date when bringing over an article originally written outside WordPress).
The management controls don’t seem to show me both copies. I haven’t checked carefully to see if the text of the article is different in the two versions, but probably not. My guess is that the list of permalink aliases is write-only, and never gets entries deleted, but I haven’t found where that is yet (it’s not in the .htaccess file, it’s not doing it just at the Apache level).
It’s also not especially serious, just amusing.