Strange Routing Behaviour - is that intended?

1

My setup:
Gateway:

apiVersion: networking.istio.io/v1beta1
kind: Gateway
metadata:
  name: mygateway
spec:
  selector:
    istio: ingressgateway # use istio default controller
  servers:
  - port:
      number: 443
      name: https
      protocol: HTTPS
    hosts:
    - host-a.example.com
    tls:
      mode: SIMPLE
      credentialName: istio-ingressgateway-certs-tls

Virualhost:

kind: VirtualService
metadata:
  name: myapp
spec:
  hosts:
    - host-a.example.com
  gateways:
  - my-istio-system/my-gateway
  http:
  - name: myapp
    match:
    - uri:
        prefix: /fancy
    route:
    - destination:
        host: myapp # must match service
        port:
          number: 80

Service Endpoints and Deployment of application is implemented accodingly and imho not relevant for this question, since the issue occurs at istio ingress gateway.

I have a second host/domain host-b.example.com with another pod which is rigjht now not part of the mesh. (see gateway definition)
Idea of the test is to make sure that requests to domain (example.com) for either applications. e.g.host-a within and host-b outside of the mesh are properly routed.
My setup is running on openshift and I tested directly against the router pods and external lb.

What I observe:

HTTP Response: 404 (from curl) when I access host-b
istio system Ingress gateway logs: 404 NR route_not_found, for some reason istio tries to route requests for host-b to host-a

What I expect:

  1. Requests for domain host-1.example.com are routed/forwarded via service mesh gateway to app (routerpod->ingressgateway->sidecar->app)
  2. Requests for domain host-2.example.com are routed/forwarded “directly” to app (routerpod->app)
2

$ istioctl proxy-config routes -n my-istio-system pod/istio-ingressgateway-123

NAME                                           DOMAINS               MATCH     VIRTUAL SERVICE
https.443.https.my-gateway.my-istio-system     host-a.example.com    /fancy*   app.my-app

Test:
curl -ksS --resolve host-a.example.com:443:(ip router pod) https://host-a.example.com/
curl -ksS --resolve host-b.example.com:443:(ip router pod) https://host-b.example.com/
curl -ksS --resolve host-b.example.com:443:(ip Load Balancer) https://host-b.example.com/
curl -ksS --resolve host-b.example.com:443:(ip Load Balancer) https://host-b.example.com/

(I added this, becuase as newbie I am not allowed to post more than 4 urls in the topic)