On the site I administer, we use WP as a CMS - only Pages, not Posts.
One of the pages in particular - the one that holds our sitemap - is returning a 404 status code to Google, so it's not getting crawled, and Webmaster Tools shows a crawl error. However, the correct page content still appears when I browse to the page in FF or IE. Double checking the status code reveals that the server does in fact give a 404 code along with the correct content.
I have disabled all the plug-ins and the error still appears, leading me to believe this problem is within WP. This is the only page that returns a 404 error, all the others return 200.
Any idea why this particular page would return an incorrect status code, without redirecting to the 404 template set up in WP?