Our system setup consists of two Weblogic 10.3 servers: one hosts the presentation layer and the other hosts the EJBs. The system runs fine under moderate load for some time (one to several days) after which EJB method calls from the presentation server to the EJB server start to fail with the following error:

java.rmi.RemoteException: java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: java.io.OptionalDataException

Stack trace:

java.io.OptionalDataException
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1349)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
    at weblogic.utils.io.ChunkedObjectInputStream.readObject(ChunkedObjectInputStream.java:197)
    at weblogic.rjvm.MsgAbbrevInputStream.readObject(MsgAbbrevInputStream.java:564)
    at weblogic.utils.io.ChunkedObjectInputStream.readObject(ChunkedObjectInputStream.java:193)
    at weblogic.jndi.internal.RootNamingNode_WLSkel.invoke(Unknown Source)
    at weblogic.rmi.internal.BasicServerRef.invoke(BasicServerRef.java:589)
    at weblogic.rmi.cluster.ClusterableServerRef.invoke(ClusterableServerRef.java:230)
    at weblogic.rmi.internal.BasicServerRef$1.run(BasicServerRef.java:477)
    at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:363)
    at weblogic.security.service.SecurityManager.runAs(Unknown Source)
    at weblogic.rmi.internal.BasicServerRef.handleRequest(BasicServerRef.java:473)
    at weblogic.rmi.internal.wls.WLSExecuteRequest.run(WLSExecuteRequest.java:118)

Once the first OptionalDataException is encountered all subsequent calls fail with the same result. Some sources suggest that this might be related to cluster multicast port being misconfigured. However, these servers do not belong to a cluster.

Booting the EJB server always temporarily resolves the issue, but the issue seems to occur again after some time.

Any ideas?