diff --git a/core/components/minishop3/src/Processors/Category/Update.php b/core/components/minishop3/src/Processors/Category/Update.php
index 0b386940..71a8501e 100644
--- a/core/components/minishop3/src/Processors/Category/Update.php
+++ b/core/components/minishop3/src/Processors/Category/Update.php
@@ -2,40 +2,20 @@
 
 namespace MiniShop3\Processors\Category;
 
-use MODX\Revolution\Processors\Resource\Update as UpdateProcessor;
 use MiniShop3\Model\msCategory;
-use MODX\Revolution\modResource;
+use MiniShop3\Processors\Resource\EnsureTargetClassKeyTrait;
+use MODX\Revolution\Processors\Resource\Update as UpdateProcessor;
 
 class Update extends UpdateProcessor
 {
+    use EnsureTargetClassKeyTrait;
+
     public $classKey = msCategory::class;
     public $languageTopics = ['resource', 'minishop3:default'];
     public $permission = 'mscategory_save';
     public $beforeSaveEvent = 'OnBeforeDocFormSave';
     public $afterSaveEvent = 'OnDocFormSave';
 
-    /**
-     * @return bool|null|string
-     */
-    public function initialize()
-    {
-        $primaryKey = $this->getProperty($this->primaryKeyField, false);
-        if (empty($primaryKey)) {
-            return $this->modx->lexicon($this->classKey . '_err_ns');
-        }
-
-        if (!$this->modx->getCount($this->classKey, ['id' => $primaryKey, 'class_key' => $this->classKey])) {
-            $res = $this->modx->getObject(modResource::class, ['id' => $primaryKey]);
-            if ($res) {
-                $res->set('class_key', $this->classKey);
-                $res->save();
-            }
-        }
-
-        return parent::initialize();
-    }
-
-
     /**
      * @return int|mixed|string
      */
diff --git a/core/components/minishop3/src/Processors/Product/Update.php b/core/components/minishop3/src/Processors/Product/Update.php
index 4bc07eb3..882f6b53 100644
--- a/core/components/minishop3/src/Processors/Product/Update.php
+++ b/core/components/minishop3/src/Processors/Product/Update.php
@@ -4,6 +4,7 @@
 
 use MiniShop3\Model\msCategory;
 use MiniShop3\Model\msProduct;
+use MiniShop3\Processors\Resource\EnsureTargetClassKeyTrait;
 use MiniShop3\Utils\Utils;
 use MODX\Revolution\modX;
 use MODX\Revolution\Processors\Processor;
@@ -11,6 +12,7 @@
 
 class Update extends UpdateProcessor
 {
+    use EnsureTargetClassKeyTrait;
     use ProductDataPayloadTrait;
 
     public $classKey = msProduct::class;
diff --git a/core/components/minishop3/src/Processors/Resource/EnsureTargetClassKeyTrait.php b/core/components/minishop3/src/Processors/Resource/EnsureTargetClassKeyTrait.php
new file mode 100644
index 00000000..15bda914
--- /dev/null
+++ b/core/components/minishop3/src/Processors/Resource/EnsureTargetClassKeyTrait.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MiniShop3\Processors\Resource;
+
+use MODX\Revolution\modResource;
+
+/**
+ * Allows Resource Update processors to load the object when class_key is being changed
+ * (e.g. modDocument → msProduct) before parent::initialize() runs getObject($classKey).
+ *
+ * @property \MODX\Revolution\modX $modx
+ * @property string $classKey
+ * @property string $primaryKeyField
+ */
+trait EnsureTargetClassKeyTrait
+{
+    /**
+     * @return bool|null|string
+     */
+    public function initialize()
+    {
+        $err = $this->ensureTargetClassKeyExists();
+        if ($err !== null) {
+            return $err;
+        }
+
+        return parent::initialize();
+    }
+
+    /**
+     * @return string|null Error lexicon string or null on success
+     */
+    protected function ensureTargetClassKeyExists(): ?string
+    {
+        $primaryKey = $this->getProperty($this->primaryKeyField, false);
+        if (empty($primaryKey)) {
+            return $this->modx->lexicon($this->classKey . '_err_ns');
+        }
+
+        if (!$this->modx->getCount($this->classKey, ['id' => $primaryKey, 'class_key' => $this->classKey])) {
+            $res = $this->modx->getObject(modResource::class, ['id' => $primaryKey]);
+            if ($res) {
+                $res->set('class_key', $this->classKey);
+                $res->save();
+            }
+        }
+
+        return null;
+    }
+}