It’s acting as if memory.oom.group is set to 1, even though it’s not:

dullbananas:~$ cat /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/app.slice/app-gnome-codium-158608.scope/memory.oom.group 
0
dullbananas:~$ cat /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/app.slice/memory.oom.group 
0
dullbananas:~$ cat /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/memory.oom.group 
0
dullbananas:~$ cat /sys/fs/cgroup/user.slice/user-1000.slice/memory.oom.group 
0
dullbananas:~$ cat /sys/fs/cgroup/user.slice/memory.oom.group 
0
dullbananas:~$ cat /sys/fs/cgroup/memory.oom.group 
cat: /sys/fs/cgroup/memory.oom.group: No such file or directory