When the "optional" $base_url is not specified in the /sites/default/settings.php file, notifications do not contain valid hyperlinks.
Here's an example of what I received until I modified the settings.php file:
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Comments
Comment #1
dziemecki commentedNot sure I can fix this one. Line 418 uses the core url function (http://api.drupal.org/api/4.7/function/url) to build the links. The $base_url is not called directly in that process.
Comment #2
dziemecki commentedDoesn't appear to be specific to this module.