Links not always working

I feel silly not being able to get this to work. My issue is that the links seem to be working only part of the time.

For example: On this post, the Prev & Next links are working:
http://jeffwall.ca/painting-picture-lethbridge-future/

However, on the next post, they show as links, but aren’t clickable:
http://jeffwall.ca/business-owner-time-lethbridge-city-council/

The posts listed are all in the same category. I have had this on other posts as well. I can’t tell for sure, but it may be NOT working on more posts than it’s working…

Not working:
http://jeffwall.ca/vote-lethbridge-election/
http://jeffwall.ca/can-vote-lethbridge-election/
http://jeffwall.ca/bit-jeff-wall/
http://jeffwall.ca/lethbridge-city-council-candidate-jeff-wall-publishes-facebook-page/
http://jeffwall.ca/jeff-wall-announces-city-council-candidacy-cjoc-story/
http://jeffwall.ca/business-owner-time-lethbridge-city-council/

Working:
http://jeffwall.ca/a-place-to-start/
http://jeffwall.ca/jeff-wall-announces-lethbridge-city-council-candidacy/
http://jeffwall.ca/jeff-wall-for-city-council-sign-patrol/
http://jeffwall.ca/running-lethbridge-city-council/
http://jeffwall.ca/painting-picture-lethbridge-future/

I can find no rhyme or reason to why there is any difference between the working posts and the not working posts… And this is just the listing of the “blog” category… surveys and perspectives are also posts.

The code I’m using is in my “single.php” file:

<?php previous_post_link_plus( array(
                          'max_length' => 32,
                          'format' => '&laquo; %link',
                          'link' => '%title',
                          'before' => 'previous: ',
                          'in_same_cat' => true,
                         ) ); ?>  |
<?php next_post_link_plus( array(
                          'max_length' => 32,
                          'format' => '%link &raquo;',
                          'link' => '%title',
                          'before' => 'next: ',
                          'in_same_cat' => true,
                          ) ); ?>

Help? This is an active site right now, in the midst of a municipal election, and I’m just trying to make it easier to navigate through the blog content. I really need this figured out sooner than later, if possible. Thanks!

http://wordpress.org/plugins/ambrosite-nextprevious-post-link-plus/