Going to leave this as unresolved, as I don't know if it's an "undocumented feature" or a bug.
In hooks-filters.php, there is a piece of code to check if there are comments.
"// Display comments link and edit link"
This line of code:
elseif ($postcommentnumber == '0') ...
doesn't work with my Blog (blog.wisefaq.com), as get-comments-number is returning "-1".
Changing the line to
else
seems to resolve the issue.
But I don't know if:
* this is the right fix?
* what is causing a negative value (DISQUS perhaps?)
Dale