1. Create an HC on Azure with --registry-overrides=registry.build09.ci.openshift.org/ci-ln-by1nnb2/release=preservehypershiftaks.azurecr.io/release,registry.build09.ci.openshift.org/ci-ln-by1nnb2/stable=preservehypershiftaks.azurecr.io/release 

2. Check image used by CVO's main container
oc get deploy cluster-version-operator -n clusters-fxie-test -o jsonpath='{.spec.template.spec.containers[0].image}'
registry.build09.ci.openshift.org/ci-ln-by1nnb2/release:latest

CVO should be using images from preservehypershiftaks.azurecr.io

The main CVO container uses the release image specified on the HCP resource directly:
https://github.com/openshift/hypershift/blob/d4190487138083a624b181bfab66f42912fa49d3/control-plane-operator/controllers/hostedcontrolplane/cvo/params.go#L30