Started container with docker run, now it is not showing up in docker ps -a

I started a docker container with docker run, like this:

docker run 
-d 
--name plex 
--restart unless-stopped 
--network=host 
-e TZ="<timezone>" 
-e PLEX_CLAIM="<claimToken>" 
-v <path/to/plex/database>:/config 
-v <path/to/transcode/temp>:/transcode 
-v <path/to/media>:/data 
plexinc/pms-docker

Link to GitHub.com/plexinc/pms-docker

The docker container is running, as Im able to access the port and service, but I can’t seem to list the container when Im running sudo docker ps -a or sudo docker ps -aq or sudo docker ps --filter "name=plex"

I tried to run pstree, and got this output:

systemd─┬─accounts-daemon───2*[{accounts-daemon}]
        ├─agetty
        ├─atd
        ├─containerd───14*[{containerd}]
        ├─cron
        ├─dbus-daemon
        ├─dockerd─┬─docker-containe─┬─docker-containe─┬─s6-svscan─┬─s6-supervise
        │         │                 │                 │           └─s6-supervise───python───{python}
        │         │                 │                 └─9*[{docker-containe}]
        │         │                 └─17*[{docker-containe}]
        │         ├─docker-proxy───6*[{docker-proxy}]
        │         └─21*[{dockerd}]
        ├─dockerd─┬─containerd─┬─containerd-shim─┬─s6-svscan─┬─s6-supervise
        │         │            │                 │           └─s6-supervise───sh───Plex Media Serv─┬─Plex DLNA Serve───16*[{Plex DLNA Serve}]
        │         │            │                 │                                                 ├─Plex Script Hos───13*[{Plex Script Hos}]
        │         │            │                 │                                                 ├─Plex Script Hos───9*[{Plex Script Hos}]
        │         │            │                 │                                                 ├─Plex Tuner Serv───10*[{Plex Tuner Serv}]
        │         │            │                 │                                                 └─28*[{Plex Media Serv}]
        │         │            │                 └─9*[{containerd-shim}]
        │         │            └─17*[{containerd}]
        │         └─20*[{dockerd}]

So it is clearly running in docker. How do I restart or rebuild this container when I can’t seem to get the ID from docker ps -a? sudo docker stop plex or sudo docker restart plex does not work either.

Edit:

Sorry, did not include os and docker. Im running on Ubuntu server Ubuntu 18.10 (GNU/Linux 4.18.0-15-generic x86_64)

Docker version 18.09.1, build 4c52b90

Edit 2:

sudo ps aux |grep lex output:

root      2392  0.0  0.0    196     4 ?        S    17:53   0:00 s6-supervise plex
HOMEUSER     2394  0.0  0.0   4504   752 ?        Ss   17:53   0:00 /bin/sh -c LD_LIBRARY_PATH=/usr/lib/plexmediaserver:/usr/lib/plexmediaserver/lib /usr/lib/plexmediaserver/Plex Media Server
HOMEUSER     2402  1.6  0.5 707684 91316 ?        Sl   17:53   2:47 /usr/lib/plexmediaserver/Plex Media Server
HOMEUSER     2458  0.1  0.3 1791280 55380 ?       SNl  17:53   0:17 Plex Plug-in [com.plexapp.system] /usr/lib/plexmediaserver/Resources/Plug-ins-cc260c476/Framework.bundle/Contents/Resources/Versions/2/Python/bootstrap.py --server-version 1.14.1.5488-cc260c476 /usr/lib/plexmediaserver/Resources/Plug-ins-cc260c476/System.bundle
HOMEUSER     3134  0.2  0.1 373108 22540 ?        Sl   17:53   0:22 /usr/lib/plexmediaserver/Plex DLNA Server
HOMEUSER     3137  0.0  0.0 372964 15276 ?        Sl   17:53   0:00 /usr/lib/plexmediaserver/Plex Tuner Service /usr/lib/plexmediaserver/Resources/Tuner/Private /usr/lib/plexmediaserver/Resources/Tuner/Shared 1.14.1.5488-cc260c476 32600 /waitmutex
HOMEUSER     6382  0.0  0.0   7980   896 pts/1    S+   20:45   0:00 grep --color=auto lex

Answer

Had installed docker twice. Once with apt-get and once with snap.

Completely removed docker, both from apt and snap, and installed just using apt-get, and now the plex container is visible using docker ps -a.