Product Listing for tabular layout returning all but 1 result

I'm not sure if our site was upgrade or went through a fresh install, but either way we went from 1.3.9h to 1.5.5

I do not see any log files pertaining to this issue. In the tabular layout, it shows "Displaying 1 to 6 (of 6 products)" but only 5 are populated. The last one is always left off. This happens no matter the number of products assigned to a category (ex: 25/26, 6/7, and so on)

I thought I narrowed down the problem to either includes/modules/your_temp/product_listing.php or includes/templates/your_temp/common/tpl_tabular_display.php but I just haven't been able to find the culprit.

Any thoughts. You can see the problem here:

g e t 2 I t p a r t s . c o m /Index.php?main_page=index&cPath=135107_135090_119246_120153

Thanks

Is there any other information I might be able to provide which would help in finding a solution?