'EventStream error' every 5 seconds when behind traefik

[andzno1]

When using Navidrome behind traefik everything seems to work just fine. I can browse my whole music library and I can listen to my music. But when I open the browser console I am seeing an EventStream error every five seconds.

This gets printed into the console:

GET https://navidrome.*******.***/api/events?jwt=********************************************************** net::ERR_CONNECTION_CLOSED 200 (OK)

And this is an example onerror event (related code location):

{
  "isTrusted": true,
  "type": "error",
  "target": {
    "url": "https://navidrome.*******.***/api/events?jwt=**********************************************************",
    "withCredentials": false,
    "readyState": 0,
    "onopen": null,
    "onmessage": null,
    "onerror": {},
    "CONNECTING": 0,
    "OPEN": 1,
    "CLOSED": 2,
    "close": {},
    "addEventListener": {},
    "dispatchEvent": {},
    "removeEventListener": {}
  },
  "currentTarget": {
    "url": "https://navidrome.*******.***/api/events?jwt=**********************************************************",
    "withCredentials": false,
    "readyState": 0,
    "onopen": null,
    "onmessage": null,
    "onerror": {},
    "CONNECTING": 0,
    "OPEN": 1,
    "CLOSED": 2,
    "close": {},
    "addEventListener": {},
    "dispatchEvent": {},
    "removeEventListener": {}
  },
  "eventPhase": 2,
  "bubbles": false,
  "cancelable": false,
  "defaultPrevented": false,
  "composed": false,
  "timeStamp": 189877,
  "srcElement": {
    "url": "https://navidrome.*******.***/api/events?jwt=**********************************************************",
    "withCredentials": false,
    "readyState": 0,
    "onopen": null,
    "onmessage": null,
    "onerror": {},
    "CONNECTING": 0,
    "OPEN": 1,
    "CLOSED": 2,
    "close": {},
    "addEventListener": {},
    "dispatchEvent": {},
    "removeEventListener": {}
  },
  "returnValue": true,
  "cancelBubble": false,
  "NONE": 0,
  "CAPTURING_PHASE": 1,
  "AT_TARGET": 2,
  "BUBBLING_PHASE": 3,
  "composedPath": {},
  "initEvent": {},
  "preventDefault": {},
  "stopImmediatePropagation": {},
  "stopPropagation": {}
}

The related Navidrome server log looks like this (###.###.###.### is traefik's IP in the public docker network (bridge)):

time="2024-04-11T23:11:35Z" level=debug msg="Client added to EventStream broker" newClient="yyyyyyyy-yyyy-yyyy-yyyy-yyyyyyyyyyyy (******* - ###.###.###.###:42698 - xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)" numActiveClients=2
time="2024-04-11T23:11:37Z" level=debug msg="Removed client from EventStream broker" client="zzzzzzzz-zzzz-zzzz-zzzz-zzzzzzzzzzzz (******* - ###.###.###.###:42698 - xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)" numActiveClients=1
time="2024-04-11T23:11:40Z" level=debug msg="Started new EventStream connection" client="zzzzzzzz-zzzz-zzzz-zzzz-zzzzzzzzzzzz (******* - ###.###.###.###:37342 - xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)" requestId=************/**********-****** username=*******

My compose file looks like this:

name: navidrome
services:
  navidrome:
    image: deluan/navidrome:0.51.1
    container_name: navidrome
    restart: unless-stopped    
    user: 1000:1000
    ports:
      - 4533:4533
    networks:
      - public
    environment:
      ND_CONFIGFILE: /data/navidrome.toml
    volumes:
      - ./data:/data
      - /media/audio/Musik:/music:ro
    labels:
      traefik.enable: true
      traefik.http.services.navidrome-svc.loadbalancer.server.port: 4533
      traefik.http.routers.navidrome.entrypoints: websecure
      traefik.http.routers.navidrome.rule: Host(`navidrome.*******.***`)
networks:
  public:
    external: true

My entrypoint configuration looks like this:

entryPoints:
  web:
    address: :80
    http:
      redirections:
        entryPoint:
          to: websecure
          scheme: https
  websecure:
    address: :443
    http:
      tls:
        certResolver: production
        domains:
          - main: *******.***
            sans:
              - '*.*******.***' # The first asterisk is not redacted, it's a wildcard

Can somebody point me in the right direction what may be causing this? Is it related to the random(?) ports (in this example 42698, 37342) that are being used for every new connection?