Envoy based header to metadata filtering regex not working

Question

My use case is to remove query parameters from the path so the envoy ISTIO filter can filter on the basis of just APIs. I am using the below configuration it is a filtering route but also takes query parameters in the path not truncating it.

The ratelimiter service on its part does not detect any special configuration for the descriptor ("PATH", "/foo?param=value") and therfore use the default of key "PATH".

any idea why truncating regex is not working? Thanks

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: {{ template "name" . }}-httpfilter
  namespace: istio-system
spec:
  workloadSelector:
    labels:
      istio: ingressgateway
  configPatches:
  - applyTo: HTTP_FILTER
    match:
      context: GATEWAY
      listener:
          filterChain:
            filter:
              name: "envoy.filters.network.http_connection_manager"
              subFilter:
                name: "envoy.filters.http.router"
    patch:
        operation: INSERT_BEFORE
        value:
          name: envoy.filters.http.header_to_metadata
          typed_config:
            "@type": type.googleapis.com/envoy.extensions.filters.http.header_to_metadata.v3.Config
            request_rules:
            - header: ':path'
              on_header_present:
                # use an arbitary name for the namespace
                # will be used later to extract descriptor value
                metadata_namespace: qry-filter
                # use an arbitary key for the metadata
                # will be used later to extract descriptor value
                key: uri
                regex_value_rewrite:
                  pattern:
                    # regex matcher
                    # truncates parameters from path
                    regex: '^(\/[\/\d\w-]+)\??.*$'
                  substitution: '\\1'
  - applyTo: HTTP_FILTER
    match:
      context: GATEWAY
      listener:
          filterChain:
            filter:
              name: 'envoy.filters.network.http_connection_manager'
              subFilter:
                name: 'envoy.filters.http.router'
    patch:
        operation: INSERT_BEFORE
        value:
          name: envoy.filters.http.ratelimit
          typed_config:
            '@type': type.googleapis.com/envoy.extensions.filters.http.ratelimit.v3.RateLimit
            # ensure the domain matches with the domain used in the ratelimit service config
            domain: {{ template "fullname" . }}-ratelimit
            failure_mode_deny: true
            rate_limit_service:
              grpc_service:
                envoy_grpc:
                  # must match load_assignment.cluster_name from the patch to the CLUSTER above
                  cluster_name: rate_limit_cluster
                timeout: 10s
              transport_api_version: V3
  - applyTo: CLUSTER
    match:
      cluster:
        # kubernetes dns of your ratelimit service
        service: ratelimit.{{ .Values.openapi.destinationSuffix }}
    patch:
      operation: ADD
      value:
        name: rate_limit_cluster
        type: STRICT_DNS
        connect_timeout: 10s
        lb_policy: ROUND_ROBIN
        http2_protocol_options: {}
        load_assignment:
          # arbitrary  name
          cluster_name: rate_limit_cluster
          endpoints:
          - lb_endpoints:
            - endpoint:
                address:
                  socket_address:
                    # kubernetes dns of your ratelimit service
                    address: ratelimit.{{ .Values.openapi.destinationSuffix }}
                    port_value: 8081


apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: {{ template "name" . }}-virtualhost
  namespace: istio-system
spec:
  workloadSelector:
    labels:
      istio: ingressgateway
  configPatches:
    - applyTo: VIRTUAL_HOST
      match:
        context: GATEWAY
        routeConfiguration:
          vhost:
            name: ""
            route:
              action: ANY
      patch:
        operation: MERGE
        value:
          rate_limits:
          - actions: # any actions in here
              - dynamic_metadata:
                  descriptor_key: PATH
                  metadata_key:
                    key: qry-filter
                    path:
                    - key: uri

apiVersion: v1
kind: ConfigMap
metadata:
  name: ratelimit-config
data:
  config.yaml: |
    domain: {{ template "fullname" . }}-ratelimit
    descriptors:
      - key: PATH
        rate_limit:
          unit: minute
          requests_per_unit: 10