Why is not my Bean receiving the submit form?

Why my Bean is not recognizing the attribute of a simple selectOneMenu: I created in my Bean the private Long areaprevencaoId attribute. This attribute is associated with a <p:selectOneMenu>

xhtml

   <h:selectOneMenu value="#{cadastroUsuarioBean.areaPrevencaoId}">
        <f:selectItems value="#{cadastroUsuarioBean.listaAreaPrevencaoSelect}"></f:selectItems>
    </h:selectOneMenu>
    <p:commandButton action="#{cadastroUsuarioBean.incluirArea}" value="Incluir" 
        process="@this" update="panel-grid-equipe" immediate="true" />

My Bean that uses the attribute:

    public void incluirArea() {
    if (areaPrevencaoId == null) {
        messages.error("Selecione uma Equipe");
    } else {
        usuarioPrevencao.setUsuarioId(usuario.getId());
        usuarioPrevencao.setAreaprevencaoId(areaPrevencaoId);
        try {
            usuarioPrevencaoRepository.salvar(usuarioPrevencao);
            //this.listaUsuarioPrevencao = usuarioPrevencaoRepository.todosIdUsuario(usuario.getId());
        } catch (PersistenceException e) {
            messages.error("Erro ao gravar os dados da Equipe do Usuário");
        }
    }
    RequestContext.getCurrentInstance().update(Arrays.asList("msg-area-prevencao","painel-equipe"));
}