Istio1.5.3 EnvoyFilter UpstreamTlsContext not working

Networking
1

I need to enable tls renegotiation for a specific outgoing domain via egress mtls origination with Istio 1.5.3. I’m using an EnvoyFilter like below:

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: allow-tls-renegotiation
  namespace: istio-system
spec:
  configPatches:
  - applyTo: CLUSTER
    match:
      cluster:
        name: outbound|443||<domain>
        load_assignment:
          cluster_name: outbound|443||<domain>
    patch:
      operation: MERGE
      value:
        transportSocket:
          name: envoy.transport_sockets.tls
          typed_config:
              "@type": "type.googleapis.com/envoy.api.v2.auth.UpstreamTlsContext"
              allow_renegotiation: true
  workloadSelector:
    labels:
      istio: egressgateway

When I apply it the config of the corresponding UpstreamTlsContext is replaced completely and not updated as expected with the merge option of the patch.
So the resulting config looks like:

        "transportSocket": {
            "name": "envoy.transport_sockets.tls",
            "typedConfig": {
                "@type": "type.googleapis.com/envoy.api.v2.auth.UpstreamTlsContext",
                "allowRenegotiation": true
            }
        },

Instead of

        "transportSocket": {
            "name": "envoy.transport_sockets.tls",
            "typedConfig": {
                "@type": "type.googleapis.com/envoy.api.v2.auth.UpstreamTlsContext",
                "commonTlsContext": {
                    "tlsCertificates": [
                        {
                            "certificateChain": {
                                "filename": "/etc/..../tls.crt"
                            },
                            "privateKey": {
                                "filename": "[redacted]"
                            }
                        }
                    ]
                },
                "sni": "<domain>",
                "allowRenegotiation": true
            }
        },

Do someone succeed to update an object “type.googleapis.com/envoy.api.v2.auth.UpstreamTlsContext” properly with EnvoyFilter ?