RDF schema markup for unlinked template

I am using the following to create custom breadcrumb structure for different situations.

function create__custom_breadcrumbs( $breadcrumb ) {
	if ( !is_tax( ['product-categories','applications', 'parameters'] ) && !is_singular( ['products'] )) {
		return;
	}
	
  	// Breadcrumb templates.
  	$breadcrumb_template_link = '<span class="breadcrumb-link-wrap" itemprop="itemListElement" itemscope="" itemtype="https://schema.org/ListItem" property="itemListElement" typeof="ListItem"><a itemprop="item" property="item" typeof="WebPage" title="Go to %title%." href="%link%" class="%type%"><span property="name">%htitle%</span></a><meta property="position" content="%position%"></span>';
  	$breadcrumb_template_nolink = '<span class="breadcrumb-link-wrap" property="itemListElement" typeof="ListItem" itemscope="" itemtype="https://schema.org/ListItem" property="item" typeof="ListItem"><span property="item" typeof="WebPage" resource="/current-page.html" ><span property="name">%htitle%</span></span><meta property="position" content="%position%"></span>';
  
	/**
	 * Store the first and last breadcrumbs, we're rebuilding the middle part.
	 */
	$breadcrumb_root = reset( $breadcrumb->breadcrumbs );
	$breadcrumb_end  = end( $breadcrumb->breadcrumbs );
	$obj = get_term_by( 'slug', get_query_var( 'term' ), get_query_var( 'taxonomy' ) );
	$tax = $obj->taxonomy;
	$term_name = $obj->name;
	// $id = $obj->term_id;

	// print_r($obj);
	

	if ( is_tax( 'product-categories' ) ) {
		
		/**
		 * Build our custom product category breadcrumb.
		 */
		$products            = get_post_type_object( 'products' );
		$breadcrumb_title          = __( 'Products', 'products' );
		$breadcrumb_link           = get_site_url().'/'.$products->rewrite['slug'].'/';
		$breadcrumb_setup = new bcn_breadcrumb( $breadcrumb_title, $breadcrumb_template_link, [], $breadcrumb_link );
	} elseif ( is_tax( ['applications','parameters'] ) ) {

	
		
		$tax            = get_taxonomy( $tax );
		$tax_name            = $tax->label;
		$breadcrumb_title          = __( $tax_name, $tax_name );
		$breadcrumb_link           = get_site_url().'/'.$tax->rewrite['slug'].'/';
		$breadcrumb_setup = new bcn_breadcrumb( $breadcrumb_title, $breadcrumb_template_link, [], $breadcrumb_link );
		$breadcrumb_root  = new bcn_breadcrumb( $term_name, $breadcrumb_template_nolink, [], '' );
	
	} elseif ( is_singular( ['products'] ) ) {

		$breadcrumb_end = new bcn_breadcrumb( 'Home', $breadcrumb_template_link, [], get_site_url() );

		$product_id            = get_the_ID();
		$product_name = get_the_title($product_id);

		$tax            = get_the_terms( $product_id, 'product-categories' )[0];
		$tax_name            = $tax->name;
		$breadcrumb_title          = __( $tax_name, $tax_name );
		$breadcrumb_link           = get_site_url().'/product-categories/'.$tax->slug.'/';
		$breadcrumb_setup = new bcn_breadcrumb( $breadcrumb_title, $breadcrumb_template_link, [], $breadcrumb_link );
		$breadcrumb_root  = new bcn_breadcrumb( $product_name, $breadcrumb_template_nolink, [], '' );

	}

	
	/**
	 * Update the Breadcrumb NavXT object.
	 */
	$breadcrumb->breadcrumbs = [
		$breadcrumb_root,
		$breadcrumb_setup,
		$breadcrumb_end,
	];
}

The issue is with rendering of the non-link RDF schema attributes. I am trying to give the non-link template a ‘resources’ attribute, which seems to be validate markup according to https://search.google.com/structured-data/testing-tool but when I include it in this code it is not rendering the resource attribute at all.

Is there something that is removing this? If so is there a way around this?

Thanks