Evitar los post duplicados al utilizar múltiples loops en WordPress

WP_Deduplicator.php

<?php

class WP_Deduplicator {
	private static $published = array();

	public static function add( $post = null ) {
		$post = get_post( $post );
		if ( !in_array( $post->ID, self::$published ) )
			array_push( self::$published, $post->ID );
	}

	public static function get() {
		return self::$published;
	}
}


$query = new WP_Query([
	'post__not_in': WP_Deduplicator::get()
	// ...
]);


while ( $query->have_posts() ) {
	$query->the_post();
	WP_Deduplicator::add();
	// ...
}