Connection unexpectedly closed by Cached Connection Manager Debug at the end of EJB call via remote interface in JBoss EAP 7.1

Issue

• A container transaction is started for an EJB (transaction REQUIRED) method which calls another EJB (transaction REQUIRED) method via the remote interface
• During the "inner" method call a connection is obtained from a datasource, enlisted in the transaction, and "cached" (rather than being immediately closed) by an application component

• At the end of the method called via the remote interface, the connection is reported as leaked (IJ000100) and closed

  ... IJ000100: Closing a connection for you. Please close them yourself: org.jboss.jca.adapters.jdbc.jdk8.WrappedConnectionJDK8...
  

• In the outer method (still within the original transaction), use of the connection by the component which obtained it results in failure

  ... java.sql.SQLException: IJ031040: Connection is not associated with a managed connection: org.jboss.jca.adapters.jdbc.jdk8.WrappedConnectionJDK8...