That's very odd. I can't see anything in the config that would make this happen. Nor can I replicate this, using your settings, on my local installation.
Three questions spring to mind ...
Firstly, does this happen for all your users, or just one or two?
Secondly, is the Biography Box you're looking at which exhibits this behaviour automagically added to a post by the plugin or is it produced by the plugin's shortcode?
Thirdly, are there any other plugins that you have which could be interfering with the URL? Such as an SEO plugin for example. Have you tried disabling all plugins, then re-enabling WP Biographia and seeing if it still happens?