Fail to re-populate registration form with password validation

[mattdwen]

I'm using SilverStripe 3.1.5 with the latest dev-master of silverstripe-memberprofiles.

I've specified a password policy in _config.php as follows:

$passwordValidator = new PasswordValidator();
$passwordValidator->minLength(8);
$passwordValidator->characterStrength(2, array("lowercase", "uppercase", "digits", "punctuation"));
$passwordValidator->checkHistoricalPasswords(10);
Member::set_password_validator($passwordValidator);

When registering as new user on the front end of the site, and using a password which doesn't meet the criteria, the password validation fails as expected, but all submitted data in the form is wiped.

If I submit the form with another invalid field, e.g. missing a required first name, the form is re-populated as expected, with the First Name is required message, though without the password validation error.

How can I configure this so the form is re-populated when the password validation fails?