/etc/machine-id contains an ID
This was caused in df93289b by moving airootfs file copying before pacstrap.
systemd package's install file runs systemd-machine-id-setup on install which populates /etc/machine-id on airootfs that gets packed in the ISO.
/etc/machine-id will need to be removed or replaced in _cleanup.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information