fix attachment replated validation

application/Espo/Classes/FieldValidators/Attachment/Related.php

@@ -0,0 +1,47 @@
+<?php
+/************************************************************************
+ * This file is part of EspoCRM.
+ *
+ * EspoCRM - Open Source CRM application.
+ * Copyright (C) 2014-2022 Yurii Kuznietsov, Taras Machyshyn, Oleksii Avramenko
+ * Website: https://www.espocrm.com
+ *
+ * EspoCRM is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * EspoCRM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with EspoCRM. If not, see http://www.gnu.org/licenses/.
+ *
+ * The interactive user interfaces in modified source and object code versions
+ * of this program must display Appropriate Legal Notices, as required under
+ * Section 5 of the GNU General Public License version 3.
+ *
+ * In accordance with Section 7(b) of the GNU General Public License version 3,
+ * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
+ ************************************************************************/
+
+namespace Espo\Classes\FieldValidators\Attachment;
+
+use Espo\Classes\FieldValidators\LinkParentType;
+use Espo\ORM\Entity;
+
+class Related extends LinkParentType
+{
+    public function checkValid(Entity $entity, string $field): bool
+    {
+        $typeValue = $entity->get($field . 'Type');
+
+        if ($typeValue === 'TemplateManager') {
+            return true;
+        }
+
+        return parent::checkValid($entity, $field);
+    }
+}

application/Espo/Resources/metadata/entityDefs/Attachment.json

@@ -22,7 +22,8 @@
         "related": {
             "type": "linkParent",
             "noLoad": true,
-            "view": "views/attachment/fields/parent"
+            "view": "views/attachment/fields/parent",
+            "validatorClassName": "Espo\\Classes\\FieldValidators\\Attachment\\Related"
         },
         "sourceId": {
             "type": "varchar",