diff --git a/src/Base/PyObjectBase.cpp b/src/Base/PyObjectBase.cpp
index 81741839b9..b909f50d1b 100644
--- a/src/Base/PyObjectBase.cpp
+++ b/src/Base/PyObjectBase.cpp
@@ -351,6 +351,7 @@ void PyObjectBase::startNotify()
                 PyErr_Clear();
         }
         Py_DECREF(key1);
+        Py_DECREF(key2);
     }
 }