OD Master fails to authenticate diradmin, won’t accept correct password

When trying to authenticate with WorkGroup Manager, to 127.0.0.1, on a 10.5.2 Server the diradmin account is failing. I'm certain that I'm typing in the correct password. I experienced this with 10.5.1 too. Is this a known bug? Could I be doing something wrong when initially setting up the diradmin account when creating the OD Master? The only solution I know of is to change the OD Master to a OD Standalone, and then back to a Master. But this is temporary because it soon seems to forget the password again. Is there another way to fix this? Thanks, Chris