maxResponseBodyBytes exceed doesn't change response code to 500 about traefik HOT 3 OPEN

Hey @AliaksandrZhloba,

Thanks for reaching out.

Could you provide a minimal reproducible case (for instance, full Kubernetes manifest to reproduce the issue)?

In the meantime, if any community member can help us find verified steps to reproduce and fix the issue if possible, we would love the help.

from traefik.

Hello @nmengin ,

docker-compose.yml:

services:
  reverse-proxy:
    image: traefik:v2.11.2
    command: --api.insecure=true --providers.docker --entryPoints.web.address=:80 --entryPoints.websecure.address=:443
    ports:
      - "80:80"
      - "8080:8080"
      - "443:443"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

  backend:
    image: ealen/echo-server
    labels:
      - traefik.http.routers.backend.rule=Host(`echo.docker.localhost`) || PathPrefix(`/echo`)
      - traefik.http.routers.backend.entrypoints=web
      - traefik.http.services.backend.loadbalancer.server.port=80
      - traefik.http.routers.backend.middlewares=limit@docker
      - traefik.http.middlewares.limit.buffering.maxResponseBodyBytes=20000

POST echo.docker.localhost with any large body.

Tried web and websecure entrypoints - the result is the same.
Tried v2.11.2 and v3.0.0 - similar (although v3.0.0 sometimes writes ERR write: total size of 32768 exceeded allowed 20000 entryPointName=web middlewareName=limit@docker middlewareType=Buffer routerName=backend@docker to log).
When maxResponseBodyBytes=2000 - the response is 500 Internal Server Error
When maxResponseBodyBytes=20000 - the response is 200, by the body is not only trimmed but sometimes contains some trash.

from traefik.

Hey @AliaksandrZhloba,

Thanks for the additional information.
If any community member can help us to move forward on it, we would love the help.

from traefik.