I have recreated it with simple test page:

<h:form id="form">
            <h:panelGroup rendered="#{param.show}">
                <ice:dataTable value="#{myBean.list}" var="item">
                    <ice:column>#{item}</ice:column>
                </ice:dataTable>
                <h:outputText value="#{myBean.someText}"/>
                <br/>
                <h:outputText value="#{myBean.someText2}"/>
            </h:panelGroup>
</h:form>

@ManagedBean
@SessionScoped
public class MyBean implements Serializable
{
    
    private ArrayList<String> list;
    private String someText;
    private String someText2;


    public MyBean()
    { }
    
    @PostConstruct
    public void init()
    {
        String text = "number ->";
        list = new ArrayList<String>();
        for (int i = 0; i < 10; i++)
        {
            list.add(text+" "+i);
            
        }
        
        someText = "Total numbers = 10";
        someText2 = "set show=false to check is this text getter is called when rendered = false;";
    }

    public ArrayList<String> getList() {
        return list;
    }

    public void setList(ArrayList<String> list) {
        this.list = list;
    }

    public String getSomeText() {
        return someText;
    }

    public void setSomeText(String someText) {
        this.someText = someText;
    }

    public String getSomeText2() {
        return someText2;
    }

    public void setSomeText2(String someText2) {
        this.someText2 = someText2;
    }

After running this fragment, notice that getList() method is invoked when ?show=false, while getSomeText() and getSomeText2() are not called. If ?show=true all 3 getters are called.