Thanks for the quick reply Bas.
I've reinstalled the plugin, and then also re-copied all the core WP files just to make sure nothing was missing or corrupted - everything is working fine but this. Very bizarre.
Adding to the weirdness is the fact that the override is functioning as intended on every other post. So, using the following code, I generate 6 posts:
<?php query_posts('showposts=6&offset=0'); ?>
<?php while (have_posts()) : the_post(); ?>
<div <?php post_class() ?> id="post-<?php the_ID(); ?>">
<h1><a href="<?php the_permalink() ?>" rel="bookmark" title="<?php the_title(); ?>"><?php the_title(); ?></a></h1>
<?php bdw_get_fpimg($post->ID); ?>
<?php the_advanced_excerpt('length=80&use_words=0&no_custom=1&ellipsis=%26hellip;&exclude_tags=img,p,strong'); ?>
<a href="<?php the_permalink() ?>" title="<?php the_title(); ?>" class="read-more">read more</a>
<?php endwhile; ?>
You can see the result at http://openkyoto.com
Post 1: the_advanced_excerpt template tag override works
Post 2: doesn't work, but advanced_excerpt's default settings are used
Post 3: works
Post 4: doesn't work
Post 5: works
Post 6: doesn't work
You can see this behavior repeats in the center column on the site as well. Even if I remove the center column (in case multiple query_posts calls were causing the problem) the result is the same.