problem with "print $cid" in theme/vote_up_down_points.tpl.php

I have Vote Up/Down (6.x-1.0-beta4) installed in a Drupal site and I just noticed that when I click on an arrow to vote a piece of content up or down, while the vote does get stored and is visible in the database and in views, the value does not update when viewing the node or a node list.

Using firebug I found the problem was with the code that generates the vote points span element for the node in theme/vote_up_down_points.tpl.php:

<span id="vote_points_<?php print $cid; ?>" class="vote-points"><span class="<?php print $class; ?>"><?php print $points_labelled; ?></span></span>

The code results in all the nodes having the following html for the vote points span:

<span id="vote_points_" class="vote-points"><span class="positive">1 point</span></span>

So for some reason the $cid isn't being output for the span, and so, even though the code to update the points in ajax_vote_up_down.js success function does get called, the span contents aren't updated:

// Update the points
$('#' + pid).html(data);

I tried looking in the issues for this problem, and a fix for it, but couldn't find it. I apologise if I'm reporting a known issue.

paavo