Double hyphen in search results

Hi there,

I am using Yoast on my wordpress site. I have my title tags set up like this in SEO;
For posts for example:
%%title%% – %%sitename%%

In the search results I get – – showing in between the title and the site name. Should I delete the hyphen in the titles and meta options?

Thanks,

Joe

http://wordpress.org/extend/plugins/wordpress-seo/