I have a raspberry pi running OMV7 and docker and have a portainer stack to deploy several services including gluetun and transmission. Gluetun is configured with Surfshark and to only connect to Bangkok, Thailand servers, however when transmission (or qbittorrent) is started, it changes the server to Singapore

Initially I was using qbittorrent, but after noticing that speeds were slow, I added transmission and speedtest-tracker to the stack to see if the issue was the VPN speed or the torrent client. so I had both qbittorrent and transmission running. Initially everything worked fine, and I found transmission was faster. However, after a few more tweaks this issue started happening. I tried reverting to the older compose file but the issue persisted.

user@pi-omv:~ $ docker exec -it gluetun wget -qO- ifconfig.me
103.176.152.23
user@pi-omv:~ $ docker start transmission
transmission
user@pi-omv:~ $ docker exec -it gluetun wget -qO- ifconfig.me
138.199.60.16

This is my compose file. I'm deploying it as a portainer stack

services:
  gluetun:
    image: qmcgaw/gluetun:latest
    container_name: gluetun
    cap_add:
      - NET_ADMIN
    devices:
      - /dev/net/tun:/dev/net/tun
    volumes:
      - /srv/datadisk/data/appdata/gluetun:/gluetun
    environment:
      - VPN_SERVICE_PROVIDER=surfshark
      - VPN_TYPE=wireguard
      - WIREGUARD_PRIVATE_KEY=[key]
      - WIREGUARD_ADDRESSES=10.14.0.2/16
      - SERVER_COUNTRIES=Thailand
      - SERVER_CITIES=Bangkok
      - PUID=1001
      - PGID=100
      - TZ=Asia/Bangkok
      - PORT_FORWARDING=off #originally setting this to off solved it, but it started to happen again
    ports:
      - 8080:8080
      - 51340:51340/tcp #transmission port
      - 51340:51340/udp #transmission port
      - 9091:9091 #transmission webUI
      - 9092:80 #speedtest webUI
    restart: unless-stopped

transmission:
    image: lscr.io/linuxserver/transmission:latest
    container_name: transmission
    network_mode: service:gluetun
    depends_on:
      gluetun:
        condition: service_healthy
    environment:
      - PUID=1001
      - PGID=100
      - TZ=Asia/Bangkok
      - WEBUI_PORT=9091  # Set Transmission WebUI Port
      - PEERPORT=51340
    volumes:
      - /srv/datadisk/data/appdata/transmission:/config
      - /srv/datadisk/data/downloads/transmission:/downloads
      - /srv/datadisk/data/downloads/transmission/watch:/watch
    restart: unless-stopped

I'm not an expert at all and have been using online guides and chatgpt to help me build the homelab.

I've tried checking Gluetun's GitHub and online for any similar issues but can't find anything.

I've tried a few changes then redeploying, which initially seemed to solve it, but the issue would come up again on reboot or redeploy. these changes all had that effect but I couldn’t replicate them

1. changed peer port to 8080 and removed qbittorrent.
2. changed peer port back to 51340
3. removed 8080 from gluetun
4. added PORT_FORWARDING=off
5. removed PORT_FORWARDING=off
6. added to /appdata/transmission/settings.json ```

"natpmp-enabled": false,
"upnp-enabled": false,