diff --git a/src/includes/class-wordlift-post-to-jsonld-converter.php b/src/includes/class-wordlift-post-to-jsonld-converter.php
index 701e5a189..8ec201150 100644
--- a/src/includes/class-wordlift-post-to-jsonld-converter.php
+++ b/src/includes/class-wordlift-post-to-jsonld-converter.php
@@ -194,9 +194,18 @@ public function convert( $post_id, &$references = array(), &$references_infos =
 			$post_id
 		);
 
-		// Set the values returned by the filter.
-		$jsonld['author'] = $ret_val['author'];
-		$references       = $ret_val['references'];
+		// Set the values returned by the author filter.
+		/*
+		 * Do not add the author JSON-LD if an invalid author was referenced in a post.
+		 *
+		 * @see https://github.com/insideout10/wordlift-plugin/issues/1728
+		 *
+		 * @since 3.53.2
+		 */
+		if ( ! empty( $ret_val['author'] ) ) {
+			$jsonld['author'] = $ret_val['author'];
+			$references       = $ret_val['references'];
+		}
 
 		// Return the JSON-LD if filters are disabled by the client.
 		if ( $this->disable_convert_filters ) {
@@ -264,9 +273,19 @@ public function get_author( $author_id, &$references ) {
 		// Get the entity bound to this user.
 		$entity_id = $this->user_service->get_entity( $author_id );
 
-		// If there's no entity bound return a simple author structure.
-		if ( empty( $entity_id ) || 'publish' !== get_post_status( $entity_id ) ) {
+		if ( ! empty( $entity_id ) && 'publish' === get_post_status( $entity_id ) ) {
+			// Add the author to the references.
+			$author_uri   = Wordlift_Entity_Service::get_instance()->get_uri( $entity_id );
+			$references[] = $entity_id;
+
+			// Return the JSON-LD for the referenced entity.
+			return array(
+				'@id' => $author_uri,
+			);
+		}
 
+		// If there's no entity bound return a simple author structure.
+		if ( false !== get_userdata( $author_id ) ) {
 			$author            = get_the_author_meta( 'display_name', $author_id );
 			$author_first_name = get_the_author_meta( 'first_name', $author_id );
 			$author_last_name  = get_the_author_meta( 'last_name', $author_id );
@@ -282,14 +301,8 @@ public function get_author( $author_id, &$references ) {
 			);
 		}
 
-		// Add the author to the references.
-		$author_uri   = Wordlift_Entity_Service::get_instance()->get_uri( $entity_id );
-		$references[] = $entity_id;
-
-		// Return the JSON-LD for the referenced entity.
-		return array(
-			'@id' => $author_uri,
-		);
+		// No valid entity or author so return empty array
+		return array();
 	}
 
 	/**