I check the plugin and monitor the queries :
Normal front page query :
SELECT SQL_CALC_FOUND_ROWS wp_posts.*, yarpp.score FROM wp_posts join wp_yarpp_related_cache as yarpp on wp_posts.ID = yarpp.ID WHERE 1=1 AND yarpp.score >= 5 and yarpp.reference_ID = 430 AND wp_posts.post_type IN ('page', 'post') ORDER BY yarpp.score DESC limit 5
But check the "Page" query :
SELECT SQL_CALC_FOUND_ROWS wp_posts.*, yarpp.score FROM wp_posts join wp_yarpp_related_cache as yarpp on wp_posts.ID = yarpp.ID WHERE 1=1 AND yarpp.score >= 5 and yarpp.reference_ID = 430 AND wp_posts.post_type IN ('page', 'post') AND wp_posts.post_date >= '2010:08:13 00:00:00' AND wp_posts.post_date < '2010:08:14 00:00:00' ORDER BY yarpp.score DESC limit 5
Never select a row because of
wp_posts.post_date >= '2010:08:13 00:00:00' AND wp_posts.post_date < '2010:08:14 00:00:00'