Traffic with destination as service endoint considered egress traffic

I have two services which speak grpc. When the client service attempts to send traffic to a server service endpoint (pod IP:PORT) the client side istio proxy considers this traffic egress traffic (PassthroughCluster). Is this simply because the client side proxy only contains routes for service names?

[2019-11-08T00:05:20.731Z] "POST /ai.argo.viaduct.proto.v1.ViaductAPI/Query HTTP/2" 200 - "-" "-" 1241 1280 343 342 "-" "grpc-java-netty/1.21.1" "18cbd3cf-5a7e-92ee-bd69-e7639216fc77" "192.168.176.11:8085" "192.168.176.11:8085" PassthroughCluster - 192.168.176.11:8085 192.168.192.4:50630 -

We are facing similar issue, Istio telemetry is reporting destination_service_name of internal service traffic as “PasstrhoughCluster”, even though other data fields have correct Kubernetes values, for example:

istio_requests_total{connection_security_policy="none",destination_app="geocode",destination_principal="unknown",destination_service="geocode.services.svc.cluster.local",destination_service_name="PassthroughCluster",destination_service_namespace="services",destination_version="origin_feature_istio-1ce1de2998d9ee5aa6855c84e4c0ec0358e3e75c",destination_workload="geocode",destination_workload_namespace="services",instance="10.1.1.149:42422",job="istio-mesh",permissive_response_code="none",permissive_response_policyid="none",reporter="destination",request_protocol="http",response_code="200",response_flags="-",source_app="server",source_principal="unknown",source_version="origin_feature_istio-1ce1de2998d9ee5aa6855c84e4c0ec0358e3e75c",source_workload="server",source_workload_namespace="services"}	

Everything indicates that this is internal traffic (e.g. destination_service_namespace, destination_workload_namespace, destination_service are all corrected populated), except for destination_service_namespace is showing as PassthroughCluster. Any ideas why this might be happening?

@Sovietaced, have you figured out the issue with this?

Thanks!