P:autocomplete "bug" ou falha minha?

<ui:composition xmlns="http://www.w3.org/1999/xhtml"
	xmlns:ui="http://java.sun.com/jsf/facelets"
	xmlns:h="http://java.sun.com/jsf/html"
	xmlns:p="http://primefaces.org/ui"
	xmlns:f="http://java.sun.com/jsf/core"
	template="/templates/template.xhtml">
	
	<ui:define name="content">
	                    <h:form id="mainForm">
                    <p:messages autoUpdate="true" id="msgs" showDetail="true" closable="true" showSummary="false" />
	

<p:panelGrid columns="2">  
    <f:facet name="header">  
	Conta
    </f:facet>  
      	
	  <p:outputLabel value="#{msg['entity.conta.data']}" for="data" />
	  <p:calendar id="data" locale="pt" navigator="true" value="#{contaController.entity.data}"
	  required="true" 	  requiredMessage="#{msg['global.validation.required']}"
	  pattern="dd-MM-yyyy"  converterMessage="#{msg['global.validation.date']}" />
	  
	  <p:outputLabel value="#{msg['entity.conta.valor']}" for="valor" />
	  <p:inputText id="valor" value="#{contaController.entity.valor}" required="true"
	  requiredMessage="#{msg['global.validation.required']}"
	  converter="numberConverter"
	  converterMessage="#{msg['global.validation.double']}"
	  />


	  	<p:outputLabel for="desc" value="#{msg['entity.descricao']}"/>
     	<p:inputText id="desc" value="#{contaController.entity.descricao}"/>
	  
		<p:outputLabel for="obs" value="#{msg['entity.observacao']}"/>
     	<p:inputTextarea id="obs" value="#{contaController.entity.observacao}" />
	  
	  
	  <p:outputLabel value="#{msg['entity.categoria']}" for="categoria"/>         
      <p:autoComplete value="#{contaController.entity.categoria}" id="categoria" required="true" requiredMessage="#{msg['global.validation.required']}" completeMethod="#{contaController.categoriaAutoComplete}"  
                      var="p" itemLabel="#{p}" itemValue="#{p.id}" converter="#{categoriaConverter}" forceSelection="true" minQueryLength="3"/>  
                        
                          
    <f:facet name="footer">  
       	    <p:commandButton icon="ui-icon-check" value="#{msg['button.save']}" ajax="false" 
             action="#{contaController.saveOrUpdate(false)}"/>
                                        
    	    <p:commandButton icon="ui-icon-check" value="#{msg['button.saveAndContinue']}" ajax="false" 
             action="#{contaController.saveOrUpdate(true)}"  />

    	    <p:commandButton icon="ui-icon-arrowthick-1-w" value="#{msg['button.back']}" ajax="false" 
             action="#{contaController.getIndexPath}"   />
                          
             
    </f:facet>  
	</p:panelGrid>
	
</h:form>

	</ui:define>
</ui:composition>