Sometimes my users get

username: somebody
password: !password

in the e-mail after they requested a new password.

The password is generated by user_get_password() and set in the e-mail body by _user_mail_text() which uses t().

All other parameters are set, just the password is missing.

It's very seldom and it is not reproducable.

I am using Drupal 5.1.

Any ideas?