CPT > When checking "Supports > Editor" custom fields disappear

I'm using Meta Box AIO to create a CPT: "Member Contents"

Initially, I didn't need this post to support the "Editor" field, but now I do need it.

When I check the box to add it though, the other custom fields don't show up in the back end.
(The data is still there as it displays correctly on the front end).

For example, is this without supports: Editor being checked:
https://tinyurl.com/2yqcad28

And the same post with "Editor" being checked:
https://tinyurl.com/2ddk9cv6

On the Preferences > Panels, none of the custom field groups (for this post: "Member Contents Wizard" and "Roadmaps") are not listed as an option:
https://tinyurl.com/23l8kq6k

But, the they are saved as generic Custom Fields (which do not populate on the front end):

I've tried deactivating all plugins except Meta Box AIO and Meta Box but no luck.

Here's the PHP code from the CPT:

<div>
<?php
add_action( 'init', 'your_prefix_register_post_type' );
function your_prefix_register_post_type() {
	$labels = [
		'name'                     => esc_html__( 'Member Contents', 'your-textdomain' ),
		'singular_name'            => esc_html__( 'Member Content', 'your-textdomain' ),
		'add_new'                  => esc_html__( 'Add New', 'your-textdomain' ),
		'add_new_item'             => esc_html__( 'Add New Member Content', 'your-textdomain' ),
		'edit_item'                => esc_html__( 'Edit Member Content', 'your-textdomain' ),
		'new_item'                 => esc_html__( 'New Member Content', 'your-textdomain' ),
		'view_item'                => esc_html__( 'View Member Content', 'your-textdomain' ),
		'view_items'               => esc_html__( 'View Member Contents', 'your-textdomain' ),
		'search_items'             => esc_html__( 'Search Member Contents', 'your-textdomain' ),
		'not_found'                => esc_html__( 'No member contents found.', 'your-textdomain' ),
		'not_found_in_trash'       => esc_html__( 'No member contents found in Trash.', 'your-textdomain' ),
		'parent_item_colon'        => esc_html__( 'Parent Member Content:', 'your-textdomain' ),
		'all_items'                => esc_html__( 'All Member Contents', 'your-textdomain' ),
		'archives'                 => esc_html__( 'Member Content Archives', 'your-textdomain' ),
		'attributes'               => esc_html__( 'Member Content Attributes', 'your-textdomain' ),
		'insert_into_item'         => esc_html__( 'Insert into member content', 'your-textdomain' ),
		'uploaded_to_this_item'    => esc_html__( 'Uploaded to this member content', 'your-textdomain' ),
		'featured_image'           => esc_html__( 'Featured image', 'your-textdomain' ),
		'set_featured_image'       => esc_html__( 'Set featured image', 'your-textdomain' ),
		'remove_featured_image'    => esc_html__( 'Remove featured image', 'your-textdomain' ),
		'use_featured_image'       => esc_html__( 'Use as featured image', 'your-textdomain' ),
		'menu_name'                => esc_html__( 'Member Contents', 'your-textdomain' ),
		'filter_items_list'        => esc_html__( 'Filter member contents list', 'your-textdomain' ),
		'filter_by_date'           => esc_html__( '', 'your-textdomain' ),
		'items_list_navigation'    => esc_html__( 'Member Contents list navigation', 'your-textdomain' ),
		'items_list'               => esc_html__( 'Member Contents list', 'your-textdomain' ),
		'item_published'           => esc_html__( 'Member Content published.', 'your-textdomain' ),
		'item_published_privately' => esc_html__( 'Member Content published privately.', 'your-textdomain' ),
		'item_reverted_to_draft'   => esc_html__( 'Member Content reverted to draft.', 'your-textdomain' ),
		'item_scheduled'           => esc_html__( 'Member Content scheduled.', 'your-textdomain' ),
		'item_updated'             => esc_html__( 'Member Content updated.', 'your-textdomain' ),
		'text_domain'              => esc_html__( 'your-textdomain', 'your-textdomain' ),
	];
	$args = [
		'label'               => esc_html__( 'Member Contents', 'your-textdomain' ),
		'labels'              => $labels,
		'description'         => '',
		'public'              => true,
		'hierarchical'        => false,
		'exclude_from_search' => false,
		'publicly_queryable'  => true,
		'show_ui'             => true,
		'show_in_nav_menus'   => true,
		'show_in_admin_bar'   => true,
		'show_in_rest'        => true,
		'query_var'           => true,
		'can_export'          => true,
		'delete_with_user'    => false,
		'has_archive'         => true,
		'rest_base'           => '',
		'show_in_menu'        => true,
		'menu_position'       => '',
		'menu_icon'           => 'dashicons-lock',
		'capability_type'     => 'post',
		'supports'            => ['title', 'thumbnail', 'excerpt', 'page-attributes', 'custom-fields', 'revisions', 'editor'],
		'taxonomies'          => ['content-type', 'format', 'department', 'resource', 'community', 'training', 'content-types', 'topic'],
		'rewrite'             => [
			'with_front' => false,
		],
	];

	register_post_type( 'member-content', $args );
}
</div>