See pewresearch/pewresearch-org@5c8c1cc from refs/heads/release/5.0

blocks/post-taxonomy-terms/post-taxonomy-terms.php

@@ -55,8 +55,16 @@ public function render_block_callback( $attributes, $content, $block ) {
 			)),
 			'style' => array_key_exists('separator', $attributes) ? '--separator: "' . $attributes['separator'] . '"' : null,
 		));
-
-		$post_terms = wp_get_post_terms( get_the_ID(), $taxonomy, array( 'number' => $per_page ) );
+		$post_id = get_the_ID();
+		$parent_id = wp_get_post_parent_id($post_id);
+		$post_terms = wp_get_post_terms( $post_id, $taxonomy, array( 'number' => $per_page ) );
+		// If this is a category taxonomy block we need to check if the only term being returned is "uncategorized" and if so, we need to return an empty array so that the block will look for the parent post's terms, if available.
+		if ( 'category' === $taxonomy && 1 === count($post_terms) && 'uncategorized' === $post_terms[0]->slug ) {
+			$post_terms = array();
+		}
+		if ( 0 !== $parent_id && empty($post_terms) ) {
+			$post_terms = wp_get_post_terms( $parent_id, $taxonomy, array( 'number' => $per_page ) );
+		}
 		$markup = '';
 		if ( !empty($post_terms) && !is_wp_error($post_terms) ) {
 			$markup .= '<ul class="wp-block-prc-block-post-taxonomy-terms__list">';