javax.ejb.NoSuchEJBException: JBAS016055: EJB has been removed is thrown when StatefulSessionBean is called

Issue

Calling StatefulSessionBean rarely throws the following exceptions. What is the cause of JBAS016055: EJB has been removed?

12:03:34,439 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/stateful].[com.redhat.cee.example.servlet.TestServlet]] (http-/127.0.0.1:8080-1) JBWEB000236: Servlet.service() for servlet com.redhat.cee.example.servlet.TestServlet threw exception: javax.ejb.NoSuchEJBException: JBAS016055: EJB has been removed
    at org.jboss.as.weld.ejb.StatefulSessionObjectReferenceImpl.getBusinessObject(StatefulSessionObjectReferenceImpl.java:123) [jboss-as-weld-7.4.0.Final-redhat-19.jar:7.4.0.Final-redhat-19]
    at org.jboss.weld.bean.proxy.EnterpriseBeanProxyMethodHandler.invoke(EnterpriseBeanProxyMethodHandler.java:113) [weld-core-1.1.23.Final-redhat-1.jar:1.1.23.Final-redhat-1]
    at org.jboss.weld.bean.proxy.EnterpriseTargetBeanInstance.invoke(EnterpriseTargetBeanInstance.java:56) [weld-core-1.1.23.Final-redhat-1.jar:1.1.23.Final-redhat-1]
    at org.jboss.weld.bean.proxy.ProxyMethodHandler.invoke(ProxyMethodHandler.java:105) [weld-core-1.1.23.Final-redhat-1.jar:1.1.23.Final-redhat-1]
    at com.redhat.cee.example.ejb.CounterBean$Proxy$_$$_Weld$Proxy$.incrementAndGet(CounterBean$Proxy$_$$_Weld$Proxy$.java) [classes:]
    at com.redhat.cee.example.servlet.TestServlet.doGet(TestServlet.java:46) [classes:]