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-- update: the new Moz Pro site crawler is now live, this means we can now crawl your SNI site. If you have any queries please check this post on fixing 803 errors, or reach out to help@moz.com -- Hey there! Patrick linked to a really helpful Q&A article, but the other big cause for an 803 error would be SNI (Server Name Indication). Unfortunately I don't see the actual domain included in your question, so it's hard to be sure, but that's usually the prime suspect. Our current site crawler does not support SNI and if that is in use on your site, we will have trouble crawling it. The good news is that we have begun to develop a new crawler that supports SNI, which is currently in beta. If you're interested in being a part of the beta testing, you can head here to sign up: http://goo.gl/forms/LCvL9Ix8JDHfbAvr1 I hope that helps! Feel free to reach out to us at help@moz.com if you want to discuss these errors in greater detail on a non-public forum.

I don't think Google penalises it. We can see # sign in many meta titles to promote they are number 1 in their sector. Like they add "#1 software for xxxxx". Even I tried it and I don't see any negative impact. I guess sings might be ignored but don't cause any drop.

Is there a redirect on the page that is ranking with the term? We experienced the same thing and we found that the 301 redirect we had got erased somehow. Once we put it back in, we returned to the same position.

Marcus, The duplicate content on each product page runs at about 35%. Would that be considered a reasonable proportion? Thanks.