RealName inserts itself into auto entry user fields instead of the username and causes user selection to fail

I'm guessing this is the dumbest question in the world for this module, as it seems like this would be a module-killer right out of the gate -- but I can't find the answer through copious searches.

I have RealName installed, and is shows the FirstName LastName values from the User fields I created everywhere I expect it to -- which is great. However, when I go to many of the autocomplete fields to enter a user name, entering a user name automatically pops up a list of the RealNames for the users instead. Then it inserts the RealName I select in the user field (with no username in parentheses). When I click save, it says there is no such user -- since it is just popping in proper nouns that are not the username data.

I have seen this in a number of critical places -- like in the To field of PrivateMsgs and in other user fields I've created for users to assign themselves to events and tasks etc… These are places where regular, non-informed, non-admin users need to enter the info and are completely confused by this and brought to a halt. (At least admins like me can manually enter the real username.)

I have seen a few fields where when you enter the user field, the RealName pops us with the username following it in parentheses. When this version occurs, Drupal accepts the submission and recognizes the user chosen.

How can RealName work if it's going to universally insert itself but not do so universally in a way that sends the correct username data to Drupal?

I hope someone can help soon, b/c this is pissing off our users!