kubernetesIngressNginx extension not working with nginx.ingress.kubernetes.io/use-regex

Traefik Traefik v3 (latest)
1

I’m working on a kubernetes ingress nginx migration and have a number of existing ingress records working on the original nginx ingress controller.

I have deployed a new traefik ingress to the cluster with the kubernetesIngressNginx option enabled.

kubectl exec -it -n  traefik traefik-8d6d9b886-vbfxz -- traefik version
Version:      3.6.6
Codename:     ramequin
Go version:   go1.24.11
Built:        2025-12-29T15:47:44Z
OS/Arch:      linux/amd64

Traefik is seeing the nginx routes and creating rules for them.
I have an issue with on that is using an annotation
nginx.ingress.kubernetes.io/use-regex*:* "true"

When I access the endpoint on the nginx loadbalancer it is working but when I access it on the traefik load balancer it returns a 404.

This is listed as supported on the Traefik migration guides but Traefik it seems to be escaping the path when it creates the rule.
When I look at the output of the /api/rawdata I get this for the detected ingress


{
    "web-default-regex-test-ingress-rule-0-path-0@kubernetesingressnginx": {
        "entryPoints": [
            "websecure"
        ],
        "service": "default-regex-test-ingress-echo-service-80",
        "rule": "Host(`regex-test.example.com`) \u0026\u0026 PathRegexp(`^/api/v\\\\d\\{1\\}/users`)",
        "ruleSyntax": "default",
        "priority": 69,
        "tls": {
            "options": "default"
        },
        "observability": {
            "accessLogs": true,
            "metrics": true,
            "tracing": true,
            "traceVerbosity": "minimal"
        },
        "status": "enabled",
        "using": [
            "web"
        ]
    }
}

The ingress record is

apiVersion: networking.k8s.io/v1
kind: Ingressmeta
data:  
  annotations:    
    nginx.ingress.kubernetes.io/use-regex: "true"
  name: regex-test-ingress
  namespace: default
spec:
  ingressClassName: nginx
  rules:
  - host: regex-test.example.com
    http:
      paths:
      - backend:
          service:
            name: echo-service
            port:
              number: 80
        path: /api/v\d{1}/users
        pathType: ImplementationSpecific

The traefik pod is running with this set of options:

- args:
    - --entryPoints.metrics.address=:9100/tcp
    - --entryPoints.traefik.address=:8080/tcp
    - --entryPoints.web.address=:8000/tcp
    - --entryPoints.websecure.address=:8443/tcp
    - --api.dashboard=true
    - --ping=true
    - --metrics.prometheus=true
    - --metrics.prometheus.entrypoint=metrics
    - --providers.kubernetescrd
    - --providers.kubernetescrd.allowEmptyServices=true
    - --providers.kubernetesingress
    - --providers.kubernetesingress.allowEmptyServices=true
    - --providers.kubernetesingress.ingressendpoint.publishedservice=traefik/traefik
    - --providers.kubernetesgateway
    - --providers.kubernetesgateway.statusaddress.service.name=traefik
    - --providers.kubernetesgateway.statusaddress.service.namespace=traefik
    - --providers.kubernetesgateway.experimentalchannel=true
    - --providers.kubernetesingressnginx
    - --providers.kubernetesingressnginx.controllerclass=k8s.io/ingress-nginx
    - --providers.kubernetesingressnginx.ingressclass=nginx
    - --entryPoints.websecure.http.tls=true
    - --log.level=DEBUG
    - --accesslog=true
    - --accesslog.format=json
    - --accesslog.fields.defaultmode=keep
    - --accesslog.fields.headers.defaultmode=keep

Is there something I should be doing extra to get this configuration to work in traefik?