(7.2.z) EJBContextMultipleSDTestCase fails in many PRs

Many open PRs are randomly failing. One of most failed tests is EJBContextMultipleSDTestCase. Example can be found here:

http://brontes.lab.eng.brq.redhat.com/buildConfiguration/Eap73x_PullRequest_LinuxElytronJdk8/168263?

This issue appears on most open PRs on task "Linux - elytron - JDK8".

Failed tests:

EJBContextMultipleSDTestCase.firstTestorg.jboss.as.test.integration.ejb.security
EJBContextMultipleSDTestCase.secondTestorg.jboss.as.test.integration.ejb.security

Part of stacktrace:
org.jboss.ejb.client.RequestSendFailedException: EJBCLIENT000409: No more destinations are available
  at org.jboss.ejb.client.EJBClientInvocationContext.getResult(EJBClientInvocationContext.java:622)
  at org.jboss.ejb.client.EJBClientInvocationContext.getResult(EJBClientInvocationContext.java:553)
  at org.jboss.ejb.protocol.remote.RemotingEJBClientInterceptor.handleInvocationResult(RemotingEJBClientInterceptor.java:57)
....
Suppressed: org.jboss.ejb.client.RequestSendFailedException: Destination @ remote+http://localhost:8080
    at org.jboss.ejb.protocol.remote.RemoteEJBReceiver$1.handleFailed(RemoteEJBReceiver.java:104)
    at org.jboss.ejb.protocol.remote.RemoteEJBReceiver$1.handleFailed(RemoteEJBReceiver.java:76)
    at org.xnio.IoFuture$HandlingNotifier.notify(IoFuture.java:215)
....
 Caused by: javax.security.sasl.SaslException: Authentication failed: all available authentication mechanisms failed:
JBOSS-LOCAL-USER: javax.security.sasl.SaslException: JBOSS-LOCAL-USER: Server rejected authentication
DIGEST-MD5: javax.security.sasl.SaslException: DIGEST-MD5: Server rejected authentication
    at org.jboss.remoting3.remote.ClientConnectionOpenListener.allMechanismsFailed(ClientConnectionOpenListener.java:109)
    at org.jboss.remoting3.remote.ClientConnectionOpenListener$Capabilities.handleEvent(ClientConnectionOpenListener.java:401)
....
 Suppressed: javax.security.sasl.SaslException: JBOSS-LOCAL-USER: Server rejected authentication
      at org.jboss.remoting3.remote.ClientConnectionOpenListener$Authentication.handleEvent(ClientConnectionOpenListener.java:735)
....
 Suppressed: javax.security.sasl.SaslException: DIGEST-MD5: Server rejected authentication
      at org.jboss.remoting3.remote.ClientConnectionOpenListener$Authentication.handleEvent(ClientConnectionOpenListener.java:735)