If a not clustered EJB application is deployed and a client try to access it by defining only one server connection the expectation is that exact this server is used and, if this server failed, the EJB can not longer be invoked.

In case of a clustered server environment this will be the case as long as there is no clustered application and the cluster subsystem is not started.
But if there is a clustered application deployed at the same time the non clustered application change the behaviour to soemwhat clustered with LB and failover.

• it is not expected that a non clustered application has some kind of LB and failover without any configuration at client side as it is intentional that there is only one server configured and the application is not clustered!
• The behaviour of application / client should not effected by other deployed applications
• The credentials are not passed to the servers which are added internaly if the configuration does not contain the "cluster" part

The same problem with the credentials is visible if there is a mix of clustered and non clustered EJB's in one application