Recently, on Google Webmaster Tools it shows under "HTML Improvements" duplicate title tags issues for some old posts, e.g.
These posts, however, are published under ONLY the actual_category (double-checked in WP admin and the database and the "uncategorized" has no posts), which means that the http://www.mysite.com/uncategorized/postname shouldn't and doesn't really exist.
I understand that maybe I first saved the post as draft without having assigned any category to it, WP automatically saved it under the "uncategorized" category and for some strange reason Googlebot got it although it was still a draft. Do you have an explanation for this?
I also realized that having the "Strip the category base..." option enabled, in the URL, one may replace the actual category slug with whatever text and it will 301 redirect to the correct URL - for example check http://yoast.com/writewhateveryouwant/wordpress-seo/ (instead of the correct http://yoast.com/articles/wordpress-seo/ where the wrong URL gets redirected to).
So, I deleted the "uncategorized" category as well as all revisions and hopefully the next time Googlebot passes by it will be 301 redirected to the correct URL and therefore there will be no duplicate issues; correct?