Another Context is already active issue

I'm get an IllegalStateException from weld in AbstractConversationContext indicating that a conversation context already exists. I hit the exception once out of about 2 dozen login attempts just after entering my username/pass into my web app.

The stack trace looks similar to issue WELD-877, but we're running 2.1.0 final and this isn't a case where a request is made to a non-existent resource.

This web app uses Primefaces jsf framework along with Spring 3, running in a tomcat 7 container.

Here is the full stack trace:

org.apache.catalina.core.StandardContext fireRequestInitEvent
SEVERE: Exception sending request initialized lifecycle event to listener instance of class org.jboss.weld.environment.servlet.Listener
java.lang.IllegalStateException: Context is already active
at org.jboss.weld.context.AbstractConversationContext.activate(AbstractConversationContext.java:245)
at org.jboss.weld.servlet.ConversationContextActivator.activateConversationContext(ConversationContextActivator.java:99)
at org.jboss.weld.servlet.HttpContextLifecycle.requestInitialized(HttpContextLifecycle.java:183)
at org.jboss.weld.servlet.WeldInitialListener.requestInitialized(WeldInitialListener.java:135)
at org.jboss.weld.servlet.api.helpers.ForwardingServletListener.requestInitialized(ForwardingServletListener.java:42)
at org.apache.catalina.core.StandardContext.fireRequestInitEvent(StandardContext.java:6050)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:167)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1008)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)