JPA child record added twice

Question

I have a data table that lists Parent items. One of the columns nests another table to list the Children. Also in this column next to the nested children datatable I have Primeface commandButton to insert a child on that item. I also have another another column with another Primeface commandButton on each row to toggle a confirmed boolean on the parent.

If I first do an add child operation, the table gets ajaxically refreshed and I see the new child record. If I then press the other button which updates the confirmed boolean on the same parent item that I just added the child record to, the table ajaxically refreshes fine, the boolean flag gets updated correctly and I still see the added child. But in reality, the second jpa update added the child record again. I don't see the duplicate child record in the table until a do a refresh on my browser.

Here is some code

public class Parent implements Serializable {
    private boolean confirmed;

    @OneToMany(fetch = FetchType.EAGER, mappedBy = "parent", cascade = CascadeType.ALL)
    @OrderBy("date")
    private Set<Child> children;

public class Child implements Serializable {
    @ManyToOne(fetch = FetchType.LAZY)
    private Parent parent;

public class Bean
public void applyAddChild() {
    newChild.setDate(new Date());
    newChild.setParent(selectedParent);
    selectedParent.getChildren().add(newChild);

    try {
        service.update(selectedParent);
        Messages.addFlashMessage("Insert Successful");
    } catch (Exception e) {
        Messages.addFlashErrorMessage(e.getMessage());
    }

    newChild = new Child();
}

public void confirmSelected() {
    selectedParent.setConfirmed(true);
    try {
        service.update(selectedParent);
        Messages.addFlashMessage("Confirmed For Parent");
    } catch (Exception e) {
            Messages.addFlashErrorMessage(e.getMessage());
    }
}

When I put a breakpoint and debug the confirmedSelected method, the children are listed as a PersistentSets

Here is the confirmed Button

<p:commandButton action="#{bean.confirmSelected()}" 
    rendered="#{not parent.confirmed}" value="Confirm?" update="@form">
    <f:setPropertyActionListener value="#{parent}" 
    target="#{bean.selectedParent}" />
</p:commandButton>

And the add Child Button

<p:commandButton oncomplete="PF('addChildDialogWv').show()" 
    update="@form" value="Add Child">
    <f:setPropertyActionListener value="#{parent}" 
    target="#{bean.selectedParent}" />
</p:commandButton>

If I hit refresh on the browser in between all the ajax refreshes things work just fine. I suppose I can not use ajax and do full redirect/refresh but I'd like to know why it's not working with Ajax.

EDIT

I was able to resolve my issue but I'm not sure if this is a Band-Aid or proper way. I'm explicitly swapping out the updated object in the datatable list.

New code --->

public class Bean
    public void applyAddChild() {
        newChild.setDate(new Date());
        newChild.setParent(selectedParent);
        selectedParent.getChildren().add(newChild);

--->    Parent updatedParent = new Parent();
        try {
--->        updatedParent = service.update(selectedParent);
            Messages.addFlashMessage("Insert Successful");
        } catch (Exception e) {
            Messages.addFlashErrorMessage(e.getMessage());
        }

--->    int index = parents.indexOf(selectedParent);
--->    parents.set(index, updatedParent);

        newChild = new Child();
}