During upgrade from OCP 4.12 to 4.13, namespaces with NetworkPolicies are not reachable

Issue

• During an upgrade from OpenShift Container Platform 4.12.45 to OpenShift Container Platform 4.13.34, Routes in namespaces where a NetworkPolicy is present are failing with a HTTP 503 error:

  $ curl -I https://example-route.apps.cl1.ocp4-sandbox.example.com
  HTTP/1.1 503 Service Unavailable
  Content-Type: text/html
  

  Once the upgrade finishes, the Route is available again and works as expected.

• Pods are not reachable during an OpenShift Container Platform Upgrade from 4.12. to 4.13 on vSphere.