Multi-Container Machine Mounts

Still having challenges with this. Given this config:

{
  "containers": [
    {
      "env": {
        "PORT": "80",
        "TINI_SUBREAPER": "1"
      },
      "healthchecks": [
        {
          "http": {
            "method": "get",
            "path": "/health",
            "port": 80,
            "scheme": "http"
          },
          "kind": "readiness",
          "name": "http",
          "success_threshold": 2,
          "timeout": 2
        }
      ],
      "image": "docker.io/actualbudget/actual-server:25.9.0-alpine@sha256:7b0ee6d9ae34d4f7dab95cec5bdd968cfe8e919f31d7bb9db98e37023ed4f798",
      "name": "actual"
    },
    {
      "depends_on": [
        {
          "condition": "healthy",
          "name": "actual"
        }
      ],
      "env": {
        "ACTUAL_SERVER_URL": "http://localhost:80"
      },
      "healthchecks": [
        {
          "http": {
            "method": "get",
            "path": "/api-docs/",
            "port": 5007,
            "scheme": "http"
          },
          "kind": "liveness",
          "name": "http",
          "success_threshold": 2,
          "timeout": 2
        }
      ],
      "image": "docker.io/jhonderson/actual-http-api:25.9.0@sha256:af818827f202f67b1b5141ccad588ae3fcefc19a25f17401dd47e5e58f67cc4d",
      "name": "http-api",
      "secrets": [
        {
          "name": "server_password",
          "env_var": "ACTUAL_SERVER_PASSWORD"
        },
        {
          "name": "http_api_key",
          "env_var": "API_KEY"
        }
      ]
    }
  ],
  "guest": {
    "cpus": 1,
    "cpu_kind": "shared",
    "memory_mb": 256
  },
  "services": [
    {
      "autostart": true,
      "autostop": "stop",
      "checks": [
        {
          "interval": "10s",
          "grace_period": "10s",
          "method": "get",
          "path": "/health",
          "protocol": "http",
          "timeout": "2s",
          "type": "http"
        }
      ],
      "concurrency": {
        "type": "connections",
        "hard_limit": 100,
        "soft_limit": 75
      },
      "internal_port": 80,
      "ports": [
        {
          "port": 80,
          "handlers": [
            "http"
          ],
          "force_https": true
        },
        {
          "port": 443,
          "handlers": [
            "tls",
            "http"
          ],
          "tls_options": {
            "alpn": [
              "http/1.1"
            ],
            "versions": [
              "TLSv1.2",
              "TLSv1.3"
            ]
          }
        }
      ],
      "protocol": "tcp"
    },
    {
      "autostart": true,
      "autostop": "stop",
      "concurrency": {
        "type": "connections",
        "hard_limit": 100,
        "soft_limit": 75
      },
      "internal_port": 5007,
      "ports": [
        {
          "port": 5007,
          "handlers": [
            "tls",
            "http"
          ],
          "tls_options": {
            "alpn": [
              "http/1.1"
            ],
            "versions": [
              "TLSv1.2",
              "TLSv1.3"
            ]
          }
        }
      ],
      "protocol": "tcp"
    }
  ],
  "mounts": [
    {
      "name": "actual_data",
      "volume": "vol_re81qgedyq0",
      "path": "/data"
    }
  ]
}

the machine is successfully created, but the volume is not mounted as I expect:

Connecting to fdaa:a:7d38:a7b:88dc:8096:cfa7:2... complete
/ # mount
none on / type overlay (rw,relatime,lowerdir=/bundles/actual/.pilot-lower:/lower/dev/vdc,upperdir=/upper/dev/vdb/upper-actual,workdir=/upper/dev/vdb/workdir-actual,uuid=on)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev type tmpfs (rw,nosuid,size=65536k,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
shm on /dev/shm type tmpfs (rw,nosuid,nodev,noexec,relatime,size=65536k)
mqueue on /dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)
sysfs on /sys type sysfs (ro,nosuid,nodev,noexec,relatime)
cgroup2 on /sys/fs/cgroup type cgroup2 (rw,nosuid,nodev,noexec,relatime)
tmpfs on /run type tmpfs (rw,nosuid,size=65536k,mode=755)
/dev/root on /.pilot/swapon type squashfs (ro,relatime,errors=continue)
/dev/root on /.pilot/tini type squashfs (ro,relatime,errors=continue)
none on /.fly type tmpfs (rw,relatime)
/dev/vdb on /.fly-upper-layer type ext4 (rw,noatime,stripe=1024)
/dev/root on /bin/swapon type squashfs (ro,relatime,errors=continue)
/ # mount | grep data
/ # df
Filesystem           1K-blocks      Used Available Use% Mounted on
none                   8154588       132   7718644   0% /
tmpfs                    65536         0     65536   0% /dev
shm                      65536         0     65536   0% /dev/shm
tmpfs                    65536         0     65536   0% /run
/dev/root               147712    147712         0 100% /.pilot/swapon
/dev/root               147712    147712         0 100% /.pilot/tini
none                    106164         0    106164   0% /.fly
/dev/vdb               8154588       132   7718644   0% /.fly-upper-layer
/dev/root               147712    147712         0 100% /bin/swapo