ClassCastException when accessing passivated atomic map

Here's the scenario.
1. Create cache entry with atomic map value.
2. Allow cache entry to passivate.
3. Update cache entry.

Debugging indicates that the problematic MarshalledValue's content is an AtomicHashMap.

2010-09-21 15:39:34,963 DEBUG [org.jboss.web.tomcat.service.session.JBossCacheManager.http-attr-pass] (http-localhost%2F127.0.0.1-8080-13) processSessionRepl(): failed with exception: java.lang.ClassCastException: org.infinispan.marshall.MarshalledValue cannot be cast to org.infinispan.atomic.AtomicHashMap
at org.infinispan.atomic.AtomicHashMapProxy.getDeltaMapForWrite(AtomicHashMapProxy.java:78) [:4.2.0-SNAPSHOT]
at org.infinispan.atomic.AtomicHashMapProxy.put(AtomicHashMapProxy.java:154) [:4.2.0-SNAPSHOT]
at org.jboss.web.tomcat.service.session.distributedcache.ispn.AtomicMapEntry.put(AtomicMapEntry.java:72) [:1.0.0.Alpha13]
at org.jboss.web.tomcat.service.session.distributedcache.ispn.DistributedCacheManager.storeSessionData(DistributedCacheManager.java:237) [:1.0.0.Alpha13]
at org.jboss.web.tomcat.service.session.ClusteredSession.processSessionReplication(ClusteredSession.java:1148) [:6.0.0-SNAPSHOT]
at org.jboss.web.tomcat.service.session.JBossCacheManager.processSessionRepl(JBossCacheManager.java:2300) [:6.0.0-SNAPSHOT]
at org.jboss.web.tomcat.service.session.JBossCacheManager.storeSession(JBossCacheManager.java:341) [:6.0.0-SNAPSHOT]
at org.jboss.web.tomcat.service.session.InstantSnapshotManager.snapshot(InstantSnapshotManager.java:50) [:6.0.0-SNAPSHOT]
at org.jboss.web.tomcat.service.session.ClusteredSessionValve.handleRequest(ClusteredSessionValve.java:147) [:6.0.0-SNAPSHOT]
at org.jboss.web.tomcat.service.session.ClusteredSessionValve.invoke(ClusteredSessionValve.java:94) [:6.0.0-SNAPSHOT]
at org.jboss.web.tomcat.service.session.JvmRouteValve.invoke(JvmRouteValve.java:88) [:6.0.0-SNAPSHOT]
at org.jboss.web.tomcat.service.session.LockingValve.invoke(LockingValve.java:62) [:6.0.0-SNAPSHOT]
at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.event(CatalinaContext.java:285) [:1.1.0.CR3]
at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.invoke(CatalinaContext.java:261) [:1.1.0.CR3]
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:88) [:6.0.0-SNAPSHOT]
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:100) [:6.0.0-SNAPSHOT]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) [:]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [:]
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) [:6.0.0-SNAPSHOT]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [:]
at org.jboss.web.tomcat.service.request.ActiveRequestResponseCacheValve.invoke(ActiveRequestResponseCacheValve.java:53) [:6.0.0-SNAPSHOT]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:362) [:]
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [:]
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:653) [:]
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:951) [:]
at java.lang.Thread.run(Thread.java:636) [:1.6.0_20]