In tao_preprocess_node()

if (isset($vars['content']['comments'])) {
  $vars['post_object']['comments'] = $vars['content']['comments'];

This will work fine as long as the node is rendered with tao's node.tpl.php.
It breaks if we use a node template provided by a module. Advanced forum is one example. There might be others.

Possible solutions:
1) Within tao_preprocess_node(), check if the template used is tao's node.tpl.php or something provided by a module. In the latter case, don't unset the comments.
2) Move this code from tao_preprocess_node() to tao's node.tpl.php