In submit_post:

	if (isset($data['force_approved_state']))

	{

		$post_approval = ($data['force_approved_state']) ? 1 : 0;

	}

In posting.php:

if ((!$auth->acl_get('f_noapprove', $data['forum_id']) && !$auth->acl_get('m_approve', $data['forum_id'])) || !empty($post_data['force_approved_state']))

!empty($post_data['force_approved_state']) should be like this:

(isset($data['force_approved_state']) && !$data['force_approved_state'])

Otherwise !empty ignores when forcing the approved state to false and doesn't display the message requiring the post to be approved

EDIT: Also noticed that posting.php uses the wrong variable, $post_data instead of $data (fixed in the code above)