FluxCD kustomization difficulty applying patch

Question

Starting from the FluxCD two cluster example at https://github.com/fluxcd/flux2-kustomize-helm-example, I'm having difficulty applying a patch to the infrastructure GitRepo.

When applying the patch as below, I am getting the error: kustomize build failed: no resource matches strategic merge patch "HelmRelease.v2beta2.helm.toolkit.fluxcd.io/ingress-nginx.ingress-nginx": no matches for Id HelmRelease.v2beta2.helm.toolkit.fluxcd.io/ingress-nginx.ingress-nginx; failed to find unique target for patch HelmRelease.v2beta2.helm.toolkit.fluxcd.io/ingress-nginx.ingress-nginx

Moving the content of ingress-nginx.yaml into infrastructure/controllers/kustomization.yaml yields the same error

If I move the ingress-nginx.yaml to clusters/dev, and update the resources declaration to reflect the change, the patch applies correctly.

It seems that I can't apply a patch to a resource that's been defined in a GitRepo?

Relevant files below..

# clusters/dev/kustomization.yaml

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- ./flux-system
- ../base/infrastructure.yaml

patches:
  - patch: |-
      apiVersion: helm.toolkit.fluxcd.io/v2beta2
      kind: HelmRelease
      metadata:
        name: ingress-nginx
        namespace: ingress-nginx
      spec:
        values:
          controller:
            service:
              type: "LoadBalancer"

# ../base/infrastructure.yaml

---
apiVersion: kustomize.toolkit.fluxcd.io/v1
kind: Kustomization
metadata:
  name: infra-controllers
  namespace: flux-system
spec:
  interval: 1h
  retryInterval: 1m
  timeout: 5m
  sourceRef:
    kind: GitRepository
    name: flux-system
  path: ./infrastructure/controllers
  prune: true
  wait: true

# ./infrastructure/controllers

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  - ingress-nginx.yaml

and finally,

# ingress-nginx.yaml

---
apiVersion: v1
kind: Namespace
metadata:
  name: ingress-nginx
---
apiVersion: source.toolkit.fluxcd.io/v1beta2
kind: HelmRepository
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
spec:
  interval: 24h
  url: https://kubernetes.github.io/ingress-nginx
---
apiVersion: helm.toolkit.fluxcd.io/v2beta2
kind: HelmRelease
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
spec:
  interval: 30m
  chart:
    spec:
      chart: ingress-nginx
      version: "*"
      sourceRef:
        kind: HelmRepository
        name: ingress-nginx
        namespace: ingress-nginx
      interval: 12h
  values:
    controller:
      service:
        type: "NodePort"
    admissionWebhooks:
      enabled: false