FusionAuth sendSetPasswordEmail not sending Set Password Email when creating a user

I'm wanting to create a user without specifying the password and have FusionAuth send the Setup Password email. I'm using the PHP client library, and while I can create a user the email is not been sent. However manually dispatching a Reset Password email is delivered successfully.

I've configured the SMTP settings to use my Mailgun account.

Here's what I'm sending via the client;

$this->authClient->createUser(null, [
        'user' => [
            'active'               => true,
            'sendSetPasswordEmail' => true,
            'birthDate'            => '01/01/1990',
            'email'                => 'a.valid@email.co.uk',
            'firstName'            => 'John',
            'fullName'             => 'John Doe',
            'lastName'             => 'Doe',
            'middleName'           => '',
            'mobilePhone'          => +447777777777,
            'password'             => 'ForSomeReasonThisNEEDStoBeSet',
            'data'                 => [
                'identifier' => $someIdentifier
            ],
            'memberships'          => [
                ['groupId' => $myGroupId]
            ],
            'preferredLanguages'   => ['en'],
            'timezone'             => 'Europe/London',
            'twoFactorEnabled'     => false,
            'usernameStatus'       => 'ACTIVE',
            'username'             => $username,
            'verified'             => true
        ]
    ]);

Even when I'm passing the sendSetPasswordEmail the password field is still required, however the docs suggest this shouldn't be the case;

This field is optional only if sendSetPasswordEmail is set to true. By default sendSetPasswordEmail is false, and then this field will be required.

How can I get the Password Setup email to be send when creating a user? Thanks in advance

The sendSetPasswordEmail is a top level value in the JSON request. You need to move it up as a sibling to the user object.

Example:

$this->authClient->createUser(null, [
        'sendSetPasswordEmail' => true,
        'user' => [
            'active'               => true,
            'birthDate'            => '01/01/1990',
            'email'                => 'a.valid@email.co.uk',
            'firstName'            => 'John',
            'fullName'             => 'John Doe',
            'lastName'             => 'Doe',
            'middleName'           => '',
            'mobilePhone'          => +447777777777,
            'password'             => 'ForSomeReasonThisNEEDStoBeSet',
            'data'                 => [
                'identifier' => $someIdentifier
            ],
            'memberships'          => [
                ['groupId' => $myGroupId]
            ],
            'preferredLanguages'   => ['en'],
            'timezone'             => 'Europe/London',
            'twoFactorEnabled'     => false,
            'usernameStatus'       => 'ACTIVE',
            'username'             => $username,
            'verified'             => true
        ]
    ]);

Reference Create User API