I've also noticed that right after starting @Asynchronous method (with command button) I get
javax.ejb.ConcurrentAccessException: no concurrent calls on stateful bean 'jboss.j2ee:service=EJB3,name=...
(This is caused by rich:progressBar) Sad, but I can understand it. When I refresh the page there is no concurrent access exception but I can see that bean's signature is different.
Also in logs I see that asynchronous method is still running. So ! Seam has created new component (ApplicationScope) ? Why ? What happened to previous instance ?