calling getUser via the userAccessor returns null

A customer with a custom ConfluenceAuthenticator (based on the Soulwing CAS Authenticatory is reporting that their method calls for getUser in the userAccessor class are returning null.

The result is odd, because the behaviour of the authenticator is to:

1. Check whether or not they exist in Confluence
2. Create the user account via userAcessor.addUser
3. Check the user account just created.

The user has been added, and saved in Confluence's database yet the subsequent call to check if the user exists returns a null. However, if the server is bounced, the getUser query is successful

What looked to be caused by not using the userAccessor.saveUser, but implementing this method did not resolve the issue.
After reviewing the customer's source code with Paul, we suspect this problem may be caused by a particular hibernate query failing to execute:

    <query name="atluser.user_findAllUserNames"><![CDATA[
        select user.name
        from DefaultHibernateUser user
        order by user.name
 ]]></query>

Hibernate logs show null returned immediately after a user is added.