Looks like a Resin OS 2.13.6+rev2 -> balenaOS 2.69.1+rev1 host update where the supervisor container was failing with:
Apr 27 13:51:06 bf14f65 resin-supervisor[9675]: Error response from daemon: OCI runtime create failed: container_linux.go:349: starting container process caused "process_linux.go:449: container init caused \"rootfs_linux.go:58: mounting \\\"/mnt/data/apps.json\\\" to rootfs \\\"/var/lib/docker/aufs/mnt/5de491fb29fe6e2fc850bb8382a0cf363cc5820bf68ee405381f8698c972a562\\\" at \\\"/var/lib/docker/aufs/mnt/5de491fb29fe6e2fc850bb8382a0cf363cc5820bf68ee405381f8698c972a562/boot/apps.json\\\" caused \\\"not a directory\\\"\"": unknown: Are you trying to mount a directory onto a file (or vice-versa)? Check if the specified host path exists and is the expected type
removing the supervisor container to wipe the /boot/apps.json directory that had been created in the container fixed the issue and page suspected it was caused by the supervisor container being started before that file existed or at a point it was directory before it was converted to {}.
Looks like a Resin OS 2.13.6+rev2 -> balenaOS 2.69.1+rev1 host update where the supervisor container was failing with:
removing the supervisor container to wipe the /boot/apps.json directory that had been created in the container fixed the issue and page suspected it was caused by the supervisor container being started before that file existed or at a point it was directory before it was converted to {}.