EAP 6.5 client to EAP 7.1 server communication

Hi, we are working on Amdocs Kenan Billing product where the Middleware APIs are implemented using single EJB interface deployed on EAP 7.1 in domain mode (with 1 server node).
Any client programs can call this using java implementation. One such client is Webmethods where java processes are running on JBoss EAP6.5 and a java code which makes calls to the kenan EJB interface using client jars/package provided by Amdocs kenan. Amdocs has suggested to raise the below issue with Redhat for expert advice.

We have identified that the communication between this client running on EAP6.5 to the Kenan server running on EAP 7.1 take longer time and the thread dump analysis in Webmethods (client) shows that thread state shows as WAITING. But the API response times from kenan services is fine. the problem occurs for establishing the connection between client and the EJB interface running on the server.

"TriggerTask:1:VfPRTProvideKenanBillingActivation.ProvideKenanBillingActivation.ProvideKenanBillingActivation_1.Kenan:transitionTrigger" #1982 daemon prio=5 os_prio=0 tid=0x00007fad14054800 nid=0x1d629 in Object.wait() [0x00007fabf2c0a000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:502)
at org.jboss.ejb.client.EJBClientInvocationContext.awaitResponse(EJBClientInvocationContext.java:866)
- locked <0x000000073a90f3d0> (a java.lang.Object)
at org.jboss.ejb.client.EJBInvocationHandler.invoke(EJBInvocationHandler.java:177)
at org.jboss.ejb.client.EJBInvocationHandler.invoke(EJBInvocationHandler.java:112)
at com.sun.proxy.$Proxy115.execute(Unknown Source)
at com.amdocs.api.framework.client.SingleEJBInterceptor.invoke(SingleEJBInterceptor.java:53)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)