I appreciate you for getting back to this thread, @ASTexas.

Let me provide you some steps that would help you sort the name of your customer alphabetically.

 Let’s try resorting to the master name list. Here’s how:

 1. Log in to your QuickBooks Desktop and open the Write Checks window.

 2. Place the cursor in the PAY TO THE ORDER OF field and press Ctrl-L. This will open the master Name List.

 4. On the bottom part, click the Name button and select Re-sort List.

 5. Then, Restart QuickBooks.

6. Once completed, open the Invoices report to check if the name is alphabetically arranged.

If you still got the same result, you can use this article to rebuild and verify the data in QuickBooks Desktop. This will remove if there is empty or damaged information from the file that causes this issue: Fix data damage on your QuickBooks Desktop company file.

 I also encourage you to get in touch with our QuickBooks Desktop Technical Support Team by following the given steps above. They have the proper tools where you can have a viewing session to find the root cause of this issue. 

Please let me know how it goes by clicking the Reply button below. I'm always here to help if you have any other questions. Have a good one.