Vault-agent-injector fail on kv2 deleted secrets

Vault
1

Hi,
We use vault agent injector as init container in our Kubernetes cluster.
Vault is currently running with secret engine kv1 and I am working to upgrade to kv2.
It seems that our current code isn’t working on kv2 with deleted secrets.
This code example works for both kv1 and kv2:

   {{- range secrets "secretv1_2/kafka" }}
      {{- if  eq . "mainretrylevel4" }}
        {{- with secret "secretv1_2/kafka/mainretrylevel4" }}
          {{- if index .Data "data" }}
            {{- range $k, $v := .Data.data }}
              export kafka_mainretrylevel4_{{ $k }}='{{ $v }}'
              export KAFKA_MAINRETRYLEVEL4_{{ $k | toUpper }}='{{ $v }}'
            {{- end }}
          {{- else }}
            {{- range $k, $v := .Data }}
              export kafka_mainretrylevel4_{{ $k }}='{{ $v }}'
              export KAFKA_MAINRETRYLEVEL4_{{ $k | toUpper }}='{{ $v }}'
            {{- end }}
          {{- end }}
        {{- end }}
      {{- end }}
    {{- end }}

This doesn’t work for deleted secrets in kv2 that return different response.

{
  "request_id": "xx-xx-xx-xx-2b69fcf6f154",
  "lease_id": "",
  "lease_duration": 0,
  "renewable": false,
  "data": {
    "data": null
    },
    "metadata": {
      "version": 1
    }
  },
  "warnings": null
}

Not sure what is the correct way to handle the null.