Modifying the feed-rss2.php may help. But it has one disadvantage. One would probably need to renew the modification after every WP update.
That is why I think it is maybe better to look for the cause of problem and to fix that.
I have looked into the source code of your theme Sight and found in the function.php file of that theme the function seo_title(). This function is solely responsible for feed titles as you can still see in the ATOM Feeds of your blog (triple blog name and a vertical separator between the second and third title). The problem occurs even if you deactivate podPress.
A possible bug fix could be to prevent the function to alter the title if it is an request for one of the news feeds of the blog.
In order to do that modify the function as follows:
old:
function seo_title() {
global $page, $paged;
$newtitle = '';
$sep = " | "; # delimiter
$newtitle = get_bloginfo('name'); # default title
new:
function seo_title() {
global $page, $paged;
if ( is_feed() ) {
return '';
}
$newtitle = '';
$sep = " | "; # delimiter
$newtitle = get_bloginfo('name'); # default title
This way the function will in all the case which are defined in the further lines of this function without modifying the feed titles.