Editing a node where exclusive_value = false makes any previous nodes with exclusive_value = true to be = false

Essentially if you edit a node and leave 'exclusive_value' to off, then any existing nodes with exclusive_value = true are set to false

maybe something todo with this around line 90

          $old_node = $result->fetchObject();

          // Clear value on the old node.
          db_update($table)
            ->fields(array($column => 0)) // @todo - look up default value and use that.
            ->condition('entity_id', $old_node->entity_id, '=')
            ->execute();