NPE in FacetComponent

On a call to my multicore setup (with 'activity' being one of my cores):

/solr/activity/select/?q=:&fq=bucket:1000&fq=dma:%22Albuquerque%22&version=2.2&start=0&rows=0&facet=on&facet.date=time&facet.date.start=2011-02-01T04:00:00Z&facet.date.end=2011-06-11T00:00:00Z&facet.date.gap=%2B1HOUR&wt=json&qt=grid

I get a NPE in the FacetComponent patch.

SEVERE: java.lang.NullPointerException
at org.apache.solr.handler.component.FacetComponent.countFacets(FacetComponent.java:347)
at org.apache.solr.handler.component.FacetComponent.handleResponses(FacetComponent.java:257)
at org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.java:289)
at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:129)
at org.apache.solr.core.SolrCore.execute(SolrCore.java:1368)
at org.apache.solr.servlet.SolrDispatchFilter.execute(SolrDispatchFilter.java:356)
at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:252)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:851)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:278)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:300)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)

With a 500 error response.

Here is the qt=grid RequestHandler definition in the solrconfig.xml
<requestHandler name="grid" class="solr.SearchHandler">
<lst name="defaults">
<str name="echoParams">explicit</str>
<int name="rows">10</int>
<str name="shards">core-dev-01.example.com:8080/jiwire/activity,core-dev-02.example.com:8080/jiwire/activity,core-dev-03.example.com:8080/jiwire/activity,core-dev-01.example.com:8080/jiwire/activity,core-dev-01.example.com:8080/jiwire/activity2,core-dev-02.example.com:8080/jiwire/activity2,core-dev-03.example.com:8080/jiwire/activity2,core-dev-01.example.com:8080/jiwire/activity2,core-dev-01.example.com:8080/jiwire/activity3,core-dev-02.example.com:8080/jiwire/activity3,core-dev-03.example.com:8080/jiwire/activity3,core-dev-01.example.com:8080/jiwire/activity3,core-dev-01.example.com:8080/jiwire/activity4,core-dev-02.example.com:8080/jiwire/activity4,core-dev-03.example.com:8080/jiwire/activity4,core-dev-01.example.com:8080/jiwire/activity4</str>
</lst>
</requestHandler>