"If the propagated conversation cannot be restored, the container must associate the request with a new transient conversation
and throw an exception of type javax.enterprise.context.NonexistentConversationException from the restore
view phase of the JSF lifecycle"

and

"If the container rejects a request, it must associate the request with a new transient conversation
and throw an exception of type javax.enterprise.context.BusyConversationException from the restore view
phase of the JSF lifecycle"