Right - on the UI there is this RED warning - on the login page, after "correcting" the password:

Current Errors:
confirmPassword fields do not match

I guess some DOM-fu is needed to delete this message after the new password matches

This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira