actionStatus on commandButton breaks PageReference

I'm trying to add an progress indicator on a custom "Save" commandButton on a Visualforce page. The method that the button calls returns a PageReference. Once I add in the actionStatus code, I get the status indicator, but the new page is never loaded. What might be going wrong here? From other posts I thought that the rerender=none might help, but that didn't change the behavior, nor did choosing another element to rerender.

<apex:form >
    <apex:pageBlock title="Page Block" id="PageBlock" mode="edit">
        <apex:pageMessages />
        <apex:pageBlockButtons >
           <apex:actionStatus id="updatestatus" >
              <apex:facet name="start" >
                <img src="/img/loading.gif" />                    
              </apex:facet>
           </apex:actionStatus>
           <apex:commandButton value="Save" action="{!createCRs}" status="updatestatus" rerender="none"/>
           <apex:commandButton value="Cancel" action="{!cancelCRs}" immediate="true" html-formnovalidate="formnovalidate"/>                
        </apex:pageBlockButtons>

        <apex:pageBlockSection title="Form" columns="1">

[many apex:inputField rows here]              

        </apex:pageBlockSection>
    </apex:pageBlock>
</apex:form>

Thanks for your help, and let me know if I can provide anything else.