On my PC, I have some test containers running on a mounted folder.
If I forget to stop them at shutdown, docker will mount this folder but not as expected.

# Create service file

sudo tee /etc/systemd/system/docker-stop-all.service << 'EOF'
[Unit]
Description=Stop all Docker containers at shutdown
After=docker.service
Requires=docker.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/true
ExecStop=/bin/bash -c 'docker ps -q | xargs -r docker stop'

[Install]
WantedBy=multi-user.target
EOF

# Enable and start it

sudo systemctl daemon-reload
sudo systemctl enable --now docker-stop-all.service