pi-gen: /dev/nbd0 disconnected fails build

Hello pi-gen team,

I am observing a new build error in my project’s github action. Context here.

This started happening recently. I tested with the scripts that worked fine for a pi-gen build a month ago. I don’t see other related errors in the log.

Would appreciate any pointers to the root cause. Thank you!

[18:00:30] Begin /home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/stage2/03-set-timezone
[18:00:30] Begin /home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/stage2/03-set-timezone/02-run.sh

Current default time zone: 'America/Chicago'
Local time is now:      Mon Oct 25 13:00:32 CDT 2021.
Universal Time is now:  Mon Oct 25 18:00:32 UTC 2021.

[18:00:33] End /home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/stage2/03-set-timezone/02-run.sh
[18:00:33] End /home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/stage2/03-set-timezone
/home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/stage2/rootfs: 10.4 GiB (11130044416 bytes) trimmed
/home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/stage2/rootfs/sys
/home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/stage2/rootfs/proc
/home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/stage2/rootfs/dev/pts
/home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/stage2/rootfs/dev
/home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/stage2/rootfs/boot
/home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/stage2/rootfs
/dev/nbd0 disconnected
[18:00:34] End /home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/stage2
[18:00:34] Begin /home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/pi-gen-stage-ambianic
Creating backing image: image-pi-gen-stage-ambianic.qcow2 <- /home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/image-stage2.qcow2
Formatting '/home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/image-pi-gen-stage-ambianic.qcow2', fmt=qcow2 size=12884901888 backing_file=/home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/image-stage2.qcow2 cluster_size=65536 lazy_refcounts=off refcount_bits=16
read error, sector 0
mount: /home/runner/work/ambianic-rpi-image/ambianic-rpi-image/pi-gen/work/rpi/pi-gen-stage-ambianic/rootfs: special device /dev/mapper/nbd0p2 does not exist.
[18:00:34] Unloading image
Error: Process completed with exit code 32.