Adding sidecar injection to Pods in system namespaces such as knative-serving and knative-serving-ingress is not supported. This prevents customers from using OpenShift Serverless in conjunction with mTLS from OpenShift ServiceMesh. As such, all communication between an OpenShift Serverless client and a server pod is unencrypted.
  The customer is looking to have traffic into serverless pods be encrypted. This was working with non-OpenShift Knative and Istio together, but the OpenShift knative does not.