diff --git a/library/Businessprocess/BpNode.php b/library/Businessprocess/BpNode.php
index dcd60f8..7c8b9c7 100644
--- a/library/Businessprocess/BpNode.php
+++ b/library/Businessprocess/BpNode.php
@@ -277,6 +277,7 @@ class BpNode extends Node
                     $e->getMessage()
                 );
 
+                // Failing nodes are unknown
                 $this->state = 3;
             }
         }