Plex not updating

I run plex with docker on a QNAP NAS. I’m using Watchtower to update my docker images.
I have seen a few times now that Plex reports there is a new version available, but it never seems te be updated and keeps showing the message that there is a new version available (Version is now available).
When I remove the plex image manually (via portainer or docker compose -f docker-compose.yml down) and then run my script again to recreate the container, it says recreating. But after loggin into Plex again, it still reports there is a new version, so it didn’t get updated.
I’m using the following in my docker compose file:

    container_name: plex
    network_mode: host
    #image: linuxserver/plex:latest