Issue with ordering in mySQL 5.1.30

I just finished a new site running 9.6.3 / mySQL 5.1.30 / PHP Version 5.2.9. Wayfinder is not sorting the items properly. I have it set up to display in descending order (&sortOrder=`DESC`) but it’s pulling something else. I noticed an earlier version of mySQL was causing this same problem. I’m wondering if anyone else has seen this or had this issue. My solution - for now - was easy: I used Ditto instead. But I’d still like to know.