I have activate piklist demo, and it’s not publishing; The custom post type have status ‘new’.
My custom post type are not build with piklist. I used the Themosis Framework to create custom post type.
Piklist is more advanced in the creation of field in custom metabox.

But I’m sure the post is publishing.
Themosis method use a wrapper to create metabox, but it’s the default wordpress custom post type how are defined.

Does it work on the demonstration because an new custom status is set ?

Create the custom post type

PostType::make('media-brand', 'Medias Brands', 'Media brand')->set(array(
    'public'        => true,
    'menu_position' => 10,
    'supports'      => ['title','thumbnail'],
    'rewrite'       => true,
    'query_var'     => false,
    'has_archive'   => false,
    'menu_icon'     => 'dashicons-welcome-view-site'
));

A metabox :

<?php
/*
Title: Contents
Post Type: media-brand, case-study, offer, geographic-universe, contents-universe
Context: normal
Order: 2
Lock: true
Collapse: false
*/

piklist('field', array(
 'type' => 'textarea'
 ,'field' => 'heading'
 ,'label' => 'Chapeau'
 ,'description' => 'Entrez le chapeau du contenu.'
 ,'attributes' => array(
   'rows' => 10
   ,'cols' => 50
   ,'class' => 'large-text'
 )
 ,'required' => true
 ));

piklist('field', array(
    'type' => 'editor'
    ,'field' => 'description'
    ,'label' => __('Description')
    ,'description' => __('Entrez le contenu.')
    ,'value' => ''
    ,'options' => array (
      'wpautop' => true
      ,'media_buttons' => true
      ,'tabindex' => ''
      ,'editor_css' => ''
      ,'editor_class' => ''
      ,'teeny' => false
      ,'dfw' => false
      ,'tinymce' => true
      ,'quicktags' => true
    )
    ,'required' => true
  ));

Thank’s a lot.

You’re plugin is really great. Long ago I had not code with WordPress and that I had not used.
It is with pleasure that I reuses.