тут очень много с карточкой товара и импортом.

public/admin/import-old-site.php

@@ -170,6 +170,28 @@ function execute_old_site_import_batch(string $sqlPath, string $progressPath, ar
     ];
 }
 
+function normalize_old_site_product_categories(PDO $pdo): void
+{
+    $pdo->exec(
+        "UPDATE products p
+         SET p.category_id = (
+             SELECT pcl.category_id
+             FROM product_category_links pcl
+             INNER JOIN categories c ON c.id = pcl.category_id
+             WHERE pcl.product_id = p.id
+               AND c.is_active = 1
+             ORDER BY c.parent_id IS NULL, pcl.sort_order, pcl.category_id
+             LIMIT 1
+         )
+         WHERE p.legacy_path LIKE '/katalog/product/view/1/%'
+           AND EXISTS (
+               SELECT 1
+               FROM product_category_links pcl_exists
+               WHERE pcl_exists.product_id = p.id
+           )"
+    );
+}
+
 if ($_SERVER['REQUEST_METHOD'] === 'POST') {
     try {
         $action = (string) ($_POST['action'] ?? 'start');
@@ -186,6 +208,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         $progress = execute_old_site_import_batch($sqlPath, $progressPath, $progress);
 
         if (!empty($progress['done'])) {
+            normalize_old_site_product_categories(Database::pdo());
             $message = 'Импорт выполнен. SQL-команд выполнено: ' . (int) $progress['executed'] . '.';
         } else {
             $message = 'Импорт продолжается: ' . (float) $progress['percent'] . '%, команд за этот шаг: ' . (int) $progress['batch_executed'] . '.';