comments_popup_link disapearing

I have a site, https://www.penelopesloom.com, who’s home page is pretty identical to the single archived pages, yet the comments_popup_link disappears from the single pages. I have the same header section on both pages with the popup script and the same call for the link:

<?php comments_popup_link('Comment','Comment (1)','Comments (%)') ;?>

I recently upgraded from 2.0.4 to 2.0.5 and they might have disappeared at that time. If anyone can point me in the right direction to where I should look I would appreciate it.