Found the problem:
I got code from this post:
http://wp-types.com/forums/topic/multiple-sort-criteria/
…to handle multiple criteria sorting. It works great but has horrible side affect in that it breaks the admin listings as well as some other assorted listing views.
If you're curious about the code I've posted it and a question as to how to make it specific to only one list view here:
http://wp-types.com/forums/topic/multiple-sort-criteria-tweek/