Program: 123450
Project: 123450
Buggy source:
/** 
 * Disconnect the connection This function is used before delete or reconnect a connection.
 */
public void disconnect(){
  if (isConnected) {
    INodeConnector sourceNodeConnector=getSourceNodeConnector();
    if (sourceNodeConnector != null && !sourceNodeConnector.isMultiSchema()) {
      if (lineStyle.hasConnectionCategory(IConnectionCategory.CUSTOM_NAME) || isInTypes(lineStyle,EConnectionType.ITERATE,EConnectionType.ON_COMPONENT_OK,EConnectionType.ON_COMPONENT_ERROR,EConnectionType.ON_SUBJOB_OK,EConnectionType.ON_SUBJOB_ERROR,EConnectionType.RUN_IF,EConnectionType.ROUTE,EConnectionType.ROUTE_TRY,EConnectionType.ROUTE_CATCH,EConnectionType.ROUTE_FINALLY,EConnectionType.ROUTE_ENDBLOCK,EConnectionType.ROUTE_WHEN,EConnectionType.ROUTE_OTHER)) {
        source.getProcess().removeUniqueConnectionName(uniqueName);
      }
    }
    source.removeOutput(this);
    target.removeInput(this);
    boolean isChange=false;
    if (source instanceof Node) {
      List<IConnection> outputs=(List<IConnection>)((Node)source).getOutputs();
      for (      IConnection con : outputs) {
        if (con.getSource() != null && this.getSource() != null && con.getSource().equals(this.getSource())) {
          outputs.remove(con);
          source.addOutput(this);
          isChange=true;
          break;
        }
      }
    }
    if (target instanceof Node) {
      List<IConnection> inputs=(List<IConnection>)((Node)target).getInputs();
      for (      IConnection con : inputs) {
        if (con.getTarget() != null && this.getTarget() != null && con.getTarget().equals(this.getTarget())) {
          inputs.remove(con);
          target.addInput(this);
          break;
        }
      }
    }
    if (isChange) {
      source.removeOutput(this);
      target.removeInput(this);
    }
    updateAllId();
    isConnected=false;
    if (lineStyle.equals(EConnectionType.SYNCHRONIZE)) {
      for (      IElementParameter param : target.getElementParameters()) {
        if (param.isBasedOnSubjobStarts()) {
          TableController.updateSubjobStarts(target,param);
        }
      }
    }
  }
}

Fixed version (ground truth):
/** 
 * Disconnect the connection This function is used before delete or reconnect a connection.
 */
public void disconnect(){
  if (isConnected) {
    INodeConnector sourceNodeConnector=getSourceNodeConnector();
    if (sourceNodeConnector != null && !sourceNodeConnector.isMultiSchema()) {
      if (lineStyle.hasConnectionCategory(IConnectionCategory.CUSTOM_NAME) || isInTypes(lineStyle,EConnectionType.ITERATE,EConnectionType.ON_COMPONENT_OK,EConnectionType.ON_COMPONENT_ERROR,EConnectionType.ON_SUBJOB_OK,EConnectionType.ON_SUBJOB_ERROR,EConnectionType.RUN_IF,EConnectionType.ROUTE,EConnectionType.ROUTE_TRY,EConnectionType.ROUTE_CATCH,EConnectionType.ROUTE_FINALLY,EConnectionType.ROUTE_ENDBLOCK,EConnectionType.ROUTE_WHEN,EConnectionType.ROUTE_OTHER)) {
        source.getProcess().removeUniqueConnectionName(uniqueName);
      }
    }
    source.removeOutput(this);
    target.removeInput(this);
    updateAllId();
    isConnected=false;
    if (lineStyle.equals(EConnectionType.SYNCHRONIZE)) {
      for (      IElementParameter param : target.getElementParameters()) {
        if (param.isBasedOnSubjobStarts()) {
          TableController.updateSubjobStarts(target,param);
        }
      }
    }
  }
}