NPE in ForwardingContextual.toString during session failover

Please see the corresponding GlassFish issue for more information http://java.net/jira/browse/GLASSFISH-15277

GlassFish SQE has a multi-machine HA cluster setup, where during session failover of a shopping cart sample application, the following NPE is thrown is ForwardingContextual.toString

java.lang.NullPointerException
at org.jboss.weld.context.ForwardingContextual.toString(ForwardingContextual.java:53)
at java.lang.String.valueOf(String.java:2826)
at java.lang.StringBuilder.append(StringBuilder.java:115)
at org.jboss.weld.context.SerializableContextualInstanceImpl.toString(SerializableContextualInstanceImpl.java:66)
at java.lang.String.valueOf(String.java:2826)
at java.lang.StringBuilder.append(StringBuilder.java:115)
at org.jboss.weld.context.beanstore.AttributeBeanStore.attach(AttributeBeanStore.java:120)
at org.jboss.weld.context.AbstractBoundContext.activate(AbstractBoundContext.java:75)
at org.jboss.weld.servlet.WeldListener.requestInitialized(WeldListener.java:138)
at org.apache.catalina.core.StandardContext.fireRequestInitializedEvent(StandardContext.java:4544)
at org.apache.catalina.core.StandardHostValve.preInvoke(StandardHostValve.java:626)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:154)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:323)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:227)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:170)