Variable Listener. Why does all tasks assigned to employee A?

[viviRbi]

afterVariableChanged
current: (name=Employee A, tasks=[Task(6), Task(5), Task(4), Task(3), Task(2), Task(1)])
previous: null
afterVariableChanged
current: (name=Employee A, tasks=[Task(6), Task(5), Task(4), Task(3), Task(2), Task(1)])
previous: (name=Employee A, tasks=[Task(6), Task(5), Task(4), Task(3), Task(2), Task(1)])
afterVariableChanged
current: (name=Employee A, tasks=[Task(7), Task(6), Task(5), Task(4), Task(3), Task(2), Task(1)])
previous: null
afterVariableChanged
current: (name=Employee A, tasks=[Task(7), Task(6), Task(5), Task(4), Task(3), Task(2), Task(1)])
previous: (name=Employee A, tasks=[Task(7), Task(6), Task(5), Task(4), Task(3), Task(2), Task(1)])
afterVariableChanged
current: (name=Employee A, tasks=[Task(6), Task(5), Task(4), Task(3), Task(2), Task(1)])
previous: null
afterVariableChanged
afterVariableChanged
current: (name=Employee B, tasks=[Task(7)])
previous: null
afterVariableChanged
afterVariableChanged
current: (name=Employee C, tasks=[Task(7)])
previous: null
afterVariableChanged
afterVariableChanged
current:(name=Employee D, tasks=[Task(7)])
previous: null
afterVariableChanged

Here is my TaskChangeListenner

public class TaskChangeListener implements VariableListener<TimeTable, Task> {



    @Override
    public void afterVariableChanged(ScoreDirector<TimeTable> scoreDirector, Task task) {
        System.out.println("afterVariableChanged");
        updateStart(scoreDirector, task);
    }
    
   private void updateStart(ScoreDirector<TimeTable> scoreDirector, Task task){
        if (task.getEmp()== null) {
            if (task.getStartTime()!= null) {
                scoreDirector.beforeVariableChanged(task, "startTime");
                task.setStartTime(null);
                scoreDirector.afterVariableChanged(task, "startTime");
            }
            return;
        }
        Task previousTask = task.getPreviousTask();
        System.out.println("current: " +(task == null? null : task.getEployee().toString()));
        System.out.println("previous: " + (previousTask == null? null : previousTask.getEmp().toString()));

       for (Task shadowTask ....) set start and end time. Temporary comment out and run the app and got the consolve result above
        }
  }

Why is Employee B,C,and D behave that way? All tasks assigned to employee A.
Both Employee and Task is a Planning Enity class, Inside EMployee class there is a List of Task, annotate with @PlanningListVariable

Inside Task class, employee anotate with @InverseRelationShadowVariable(sourceVariableName = "tasks"), startTime is a shadow variable and endTIme is PiggybackShadowVariable

I saw in the examples no Constraints for "Each employee should start at the same time" needed. I think I did something wrong in this Listener class.