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Canonical tags should drastically help with this. The % is being generated because the URL is being encoded and has a "(" in it. Have your product page each contain their own canonical with the URL you want indexed.  Not sure which URL to use? Check your internal links and see how your site is linking to your product pages. Presumably its: http://www.company.com/ProductX-(-etc/ or http://www.company.com/ProductX-(-etc Add this URL as your canonical and the SE's will understand what page is the 'real' page. This will solve both problems from an SEO standpoint. If you want to actually stop the site from doing this, you can remove trailing slashes and encoding using HTACCESS.

Here is the info on pushstates - as mentioned above: https://developer.mozilla.org/en/DOM/Manipulating_the_browser_history