Fix common db relation insertion

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### Fixed
+
+- Fix common db relation insertion
+
 ## [2.14.0] - 2024-10-10
 
 ### Added

inc/commoninjectionlib.class.php

@@ -1606,7 +1606,7 @@ private function effectiveAddOrUpdate($injectionClass, $item, $values, $add = tr
             //CommonDBRelation are managed separately, so related field should be ignored
             // Ex : User -> groups_id -> Group_User
             // groups_id should not be injected in User (field contains group name (string))
-            if ($option !== false && isset($option['displaytype']) && $option['displaytype'] == 'relation') {
+            if ($option !== false && isset($option['displaytype']) && $option['displaytype'] == 'relation' && !($item instanceof CommonDBRelation)) {
                 continue;
             }