JSF render is not working for form element - jsf

Question

I have a composite displayed inside a dialog. I have an edit button that get the current bean #SessionScoped (item in a data table) and then update the UI. My app is very similar to a simple CRUD app like http://balusc.blogspot.com/2010/06/benefits-and-pitfalls-of-viewscoped.html.
The problem is that the UI is updated correctly when using <h:outputText/> but not when using a form element.
<h:inputTextarea value="#{cc.attrs.managedBean.assertionStatement}" />
<h:inputText value="#{cc.attrs.managedBean.assertionStatement}" />
<h:outputText value="#{cc.attrs.managedBean.assertionStatement}"/>
The UI shows an empty textarea and input but the outputText renders the correct value. The getAssertionStatement() is called 3 times which seems to be the correct behavior.
When I close the dialog and reopen it, everything (form element) is populated.
The dialog call (ag namespace is for composite component):
<p:dialog widgetVar="DataValueRuleDialog" modal="true" height="600" width="800">
<p:outputPanel id="DataValueRulePanel">
<ag:DataValueAssertion managedBean="#{dataValueAssertionController}" id="DataValueComposite" />
</p:outputPanel>
</p:dialog>
The composite that calls another composite:
<h:form id="DataValueForm">
<ag:assertionMetadataComponent
managedBean="#{cc.attrs.managedBean.dataValueAssertionBean.assertionMetadataBean}"
assertionStatementRows="5" />
<p:dataTable value="#{cc.attrs.managedBean.model}" var="item">
<p:column>
<f:facet name="header">Assertion Statement</f:facet>
<h:outputText rendered="#{item.profileBean.profileLocation == cc.attrs.managedBean.selectedComformanceProfile.name}" value="#{item.assertionMetadataBean.assertionStatement}" />
</p:column>
<p:column>
<p:commandButton rendered="#{item.profileBean.profileLocation == cc.attrs.managedBean.selectedComformanceProfile.name}" value="edit" immediate="true"
actionListener="#{cc.attrs.managedBean.editDataValueAssertion}" update=":DataValueComposite:DataValueForm">
</p:commandButton>
</p:column>
</p:dataTable>
</h:form>
When I remove the immediate=true the form is validated and since one of the required field (supposed to be populated) is missing, I got a validation error. This is why I have immediate=true but it should be necessary since all the items in the data table should be valid.