iControl transaction problem. iControl occasionally cannot delete the referenced Node object.

I wrote following code with iControl SDK for Java.

final Interfaces interfaces = new Interfaces(host, 443L, user, password);
final SystemSessionBindingStub systemSession = interfaces.getSystemSession();
systemSession.set_session_timeout(300);
systemSession.set_transaction_timeout(300);
final long sessionId = systemSession.get_session_identifier();
systemSession.setHeader("urn:iControl", "session", Long.toString(sessionId));
systemSession.start_transaction();

final LocalLBVirtualServerBindingStub localLBVirtualServer = interfaces.getLocalLBVirtualServer();
localLBVirtualServer.setHeader("urn:iControl", "session", Long.toString(sessionId));
localLBVirtualServer.delete_virtual_server(new String[]{"MyVirtualServer"});

final LocalLBPoolBindingStub lbPoolStub = interfaces.getLocalLBPool();
lbPoolStub.setHeader("urn:iControl", "session", Long.toString(sessionId));
lbPoolStub.delete_pool(new String[]{"MyPool"})

final LocalLBNodeAddressV2BindingStub lbNodeAddressV2 = interfaces.getLocalLBNodeAddressV2();
lbNodeAddressV2.setHeader("urn:iControl", "session", Long.toString(sessionId));
lbNodeAddressV2.delete_node_address(new String[]{"192.168.1.1%97"});

systemSession.submit_transaction();

System::Session::submit_transaction will occasionally throw a following exception.

Exception caught in System::urn:iControl:System/Session::submit_transaction()
Exception: Common::OperationFailed
    primary_error_code   : 17236240 (0x01070110)
    secondary_error_code : 0
    error_string         : 01070110:3: Node address '/Common/192.168.1.1%97' is referenced by a member of pool '/Common/MyPool'.

This problem occurs on "v11.5.1" , not occurs on "v11.2.1" .