I'm having a strange problem with a Wordpress site I built recently, wherein when users visit one of the website's pages via search engine (typically Google), a bit of strange markup is generated inside the footer element. That markup is an unordered list of dates linking to non-existent archive pages, and an unordered list of categories linking to non-existent category pages.
The strange thing here is that there is no code in the theme that would generate this markup, and even more peculiarly, the categories in the unordered list don't exist in the site's database. My first thought was that this could be the result of a possible malware infection, but since the links don't direct the user offsite, that seems unlikely. It would also be strange for the malware to generate problems only when the site is accessed via search engine.
I've been scouring the Internet looking for an example of this occurring, but have yet to find anything, and though I've been working in WP dev for over a year now, this is my first time encountering such a problem. So, my question is this: have any of you encountered something like this before, and if so, do you have any ideas on what could be the problem source, and/or do you have recommendations about how to go about debugging the issue?
NOTE: I have already hidden the markup using CSS for a user-facing solution, so I'm looking for an answer to help me address the problem more sustainably; i.e., finding a way to eliminate the markup in question.
Thanks!!
<ul>
<li><a href='http:/2015/10/'>October 2015</a></li>
<li><a href='http:/2015/09/'>September 2015</a></li>
<li><a href='http:/2015/07/'>July 2015</a></li>
<li><a href='http:/2015/06/'>June 2015</a></li>
</ul>
<ul>
<li class="categories">Categories<ul>
<li class="cat-item cat-item-14"><a href="/category/articlesorder/" >articles,order</a>
</li>
<li class="cat-item cat-item-13"><a href="/category/articlesus/" >articles,us</a>
</li>
<li class="cat-item cat-item-11"><a href="/category/businesswriting/" >business,writing</a>
</li>
<li class="cat-item cat-item-16"><a href="/category/englishorder/" >english,order</a>
</li>
<li class="cat-item cat-item-17"><a href="/category/serviceterm/" >service,term</a>
</li>
<li class="cat-item cat-item-12"><a href="/category/shoolbuy/" >shool,buy</a>
</li>
<li class="cat-item cat-item-18"><a href="/category/studybusiness/" >study,business</a>
</li>
<li class="cat-item cat-item-15"><a href="/category/studypapers/" >study,papers</a>
</li>
</ul></li>
</ul>
