Fix: WordPress Importer does not remap noteId in block metadata when reassigning comment IDs

src/class-wp-import.php

@@ -33,6 +33,7 @@ class WP_Import extends WP_Importer {
 	public $author_mapping       = array();
 	public $processed_terms      = array();
 	public $processed_posts      = array();
+	public $processed_comments   = array();
 	public $post_orphans         = array();
 	public $processed_menu_items = array();
 	public $menu_item_orphans    = array();
@@ -818,6 +819,7 @@ public function process_posts() {
 			if ( ! empty( $post['comments'] ) ) {
 				$this->process_post_comments( $post['comments'], (bool) $post_exists, $comment_post_id, $post );
 				unset( $post['comments'] );
+				$this->update_block_note_ids( $post_id );
 			}
 
 			if ( ! isset( $post['postmeta'] ) ) {
@@ -1095,6 +1097,10 @@ protected function process_post_comments( $comments, $post_exists, $comment_post
 				do_action( 'wp_import_insert_comment', $inserted_comment_id, $comment, $comment_post_id, $post );
 				$this->process_post_comment_metas( $inserted_comment_id, $comment['commentmeta'] );
 				$inserted_comments[ $key ] = $inserted_comment_id;
+				// Store comment ID mapping for note-type comments to update noteId references in blocks.
+				if ( isset( $comment['comment_type'] ) && 'note' === $comment['comment_type'] ) {
+					$this->processed_comments[ $key ] = $inserted_comment_id;
+				}
 				++$num_comments;
 			}
 		}
@@ -1139,6 +1145,52 @@ protected function process_post_comment_metas( $comment_id, $commentmeta ) {
 		}
 	}
 
+	/**
+	 * Update noteId references in block metadata to reflect new note-type comment IDs.
+	 *
+	 * Scans post content for Gutenberg blocks with noteId in metadata and updates
+	 * them to match the new comment IDs assigned during import. Only processes
+	 * comments with type 'note'.
+	 *
+	 * @param int $post_id The ID of the post being processed.
+	 * @return void
+	 */
+	protected function update_block_note_ids( int $post_id = 0 ): void {
+		if ( empty( $this->processed_comments ) ) {
+			return;
+		}
+
+		$post = get_post( $post_id );
+
+		if ( ! $post ) {
+			return;
+		}
+
+		$content = $post->post_content;
+		$updated = false;
+
+		foreach ( $this->processed_comments as $old_note_id => $new_note_id ) {
+			$search  = '"noteId":' . $old_note_id;
+			$replace = '"noteId":' . $new_note_id;
+
+			$new_content = str_replace( $search, $replace, $content );
+
+			if ( $new_content !== $content ) {
+				$content = $new_content;
+				$updated = true;
+			}
+		}
+
+		if ( $updated ) {
+			wp_update_post(
+				array(
+					'ID'           => $post_id,
+					'post_content' => $content,
+				)
+			);
+		}
+	}
+
 	/**
 	 * Process a single comment meta entry for an imported comment.
 	 *