As Sigil has pointed out, the News category is showing up on the main page. I guess I've never really given that much thought, but since it appears that all of the news articles all the way back to October 2005 are categorized without noinclude tags, so I guess it's always been like this. Seems this would be a good thing to send a bot after.
As mentioned here:Can we train a bot onto the News articles to make sure all of the Category tags are surrounded by noincludes and remove the News category from the Main page?