diff --git a/application/Espo/Resources/metadata/fields/duration.json b/application/Espo/Resources/metadata/fields/duration.json
index 4bd53e7f45..247d43b98c 100644
--- a/application/Espo/Resources/metadata/fields/duration.json
+++ b/application/Espo/Resources/metadata/fields/duration.json
@@ -10,6 +10,7 @@
         }
     ],
     "notCreatable": true,
+    "notMergeable": true,
     "fieldDefs": {
         "type": "int"
     }