[Brian]

I'm sorry for the inconvenience this is causing - I created a test document on my machine (OmniOutliner Pro v3.7.2 running on 10.5) and was able to sort the rows by selecting
Reorganize -> Keep Sorted -> Topic (A to Z)

That sounds pretty much like what you're describing, but maybe there's something specific to the document you're trying to sort that's tickling a bug or something. If you send the document as an attachment to the support ninjas - you can use "Send Feedback" under the help menu - we'll take a look and see if we can determine what's going on.