f:ajax render="@form" does not refresh the form immediately in production server

Question

f:ajax render="@form" refreshes the form immediately after user selects the select item in my development environment (Windows). However, this does not work on a production server (Ubuntu). The user has to refresh the page to see the update form. What could case the problem on a production server? Both environments use the same version of Tomcat (8.0.32) Here's my code snippet:

<h:form id="the-form">
    <h:panelGrid columns="1" cellpadding="10">
        <p:outputPanel>
            <p:selectOneMenu id="select_source" value="#{theBean.selectedSource}">
                <f:selectItem itemLabel="Select Source" itemValue="" />
                <f:selectItems value="#{theBean.sourceSelectItems}" />
                <f:ajax render="@form" listener="#{theBean.onSourceChange}" />
            </p:selectOneMenu>
        </p:outputPanel>
    </h:panelGrid>
</h:form>