I've spent much of the last 2 days tracking down the source of this problem, so I thought I'd share.
The title of my main RSS feed was being displayed as "Site NameSite Name - ".
I'm using the Yoast SEO plugin and a custom theme, so I spent a lot of time digging into both of those as they have filters to manipulate the page title. I finally found this line in the Redirection plugin that was causing the problem:
<title><?php echo $title.' - '; bloginfo_rss ('name'); ?></title>
I don't know why this plugin tries to do anything with the RSS feed title ... I don't think it should. I've removed the plugin from my site and just moved all of my redirects into my .htaccess file.