wrong account name URL

I have a test openid server. It has 4 accounts: admin, testid, chris.johnson and joe.bob. I pointed a client website at my test openid homesite server as the only authorized homesite for login to my client website.

Tests with the first 3 accounts (admin, testid and chris.johnson) worked as expected. When joe.bob tested his, it generated a URL which ended in betty-jane, instead of joe-bob, as expected. An account on my client (in the users table) is created with this same incorrect URL user name.

I'm baffled as to how it could have crossed the name up, as there is no and has never been a betty-jane account on the server, although there is a regular, non-OpenID account named betty.jane on the client.