Unfortunately, I can't reproduce these results. I'm not saying they are false, but that maybe they have to do with personalized results for the author. Did you try logging out and doing the same searches? There was a maximum of results from the same page that could be shown (I think it was about five), so I'm not sure how you can get this results.

Also, there's another issue. Even if you get the same webpages all the time, that doesn't mean that those aren't the same results. Especially when webpages today have a lot of different content. I.e. diversity != quality.