It seems to be a timing issue. An extra udev_settle seems to fix it:
udev_settle
eval $(fstype < "$NEWROOT")
Then rebuild the initramfs:
update-initramfs -u
To be honest I'm not exactly sure it's udev it's waiting for or whether this just introduced a delay. I don't expect it to fix much apart from the message. I still had a bootable system even with the message.
It would appear this message comes from:
eval $(fstype < "$NEWROOT")
on line 295 of:
/usr/share/ initramfs- tools/scripts/ local-top/ cryptroot
It seems to be a timing issue. An extra udev_settle seems to fix it:
udev_settle
eval $(fstype < "$NEWROOT")
Then rebuild the initramfs:
update-initramfs -u
To be honest I'm not exactly sure it's udev it's waiting for or whether this just introduced a delay. I don't expect it to fix much apart from the message. I still had a bootable system even with the message.