I just upgraded from v5.21 to v5.5.
I have a Category that is setup with a Rating Type of Contest Mode.
When I configure the Default Sort Order to Most Popular, I expect the Category to sort based on highest number of votes. However, it appears to only be willing to sort based on Filename. I have other (non-contest) Categories with other Default Sort Orders that seem to work fine.
If I go to the Category and manually change the sort option, it works fine. But, the Default Sort Order doesn't appear to work. I also tried setting it to Latest, Title, and other Default Sort Orders, but it always reverts to Filename. It definitely worked fine in 5.21.
Here is the Category in question. Let me know if you need me to PM you admin info:
http://vfrworld.com/photos/showgallery.php/cat/578