cryptsetup erroring with "Nothing to read on input" with persistence-encryption=luks

I've got a live-build project I use for a handy environment I carry around with me on a USB stick that's got everything set up just the way I like it. It's buster-based. I've got the config files for it on GitHub here: https://github.com/mmguero/deblive

Up until recently it would boot fine with encrypted persistence (with the "persistence persistence-encryption=none,luks" arguments added via "bootappend-live"). However, sometime recently something changed where when I boot the image on my laptop I get a continually-scrolling "Nothing to read on input." message before I'm even prompted for the encryption password.

Googling the error message (https://www.google.com/search?q="nothing+to+read+on+input") gives me an indication in the cryptsetup comments that "Fail if piped input dies reading nothing" but I'm not sure what that means.

If I remove luks from the persistence-encryption= options, it boots fine, but obviously I don't get my encrypted volume. The strange thing is I can boot the same ISO fine in VirtualBox without the error.

If I grep my config directory for anything to do with encryption/luks I get the following references:

https://github.com/mmguero/deblive/blob/master/build.sh#L89 - the bootappend-live settings

https://github.com/mmguero/deblive/blob/master/buster/config/hooks/normal/0991-security-performance.hook.chroot#L92 - adding CRYPTSETUP=y to /etc/cryptsetup-initramfs/conf-hook as indicated to me in a reddit post a while ago (see https://www.reddit.com/r/debian/comments/8yxiud/livebuild_issue_getting_persistence_with_luks/edlxteu/) to get encryption working in the first place... maybe this isn't needed any more?

https://github.com/mmguero/deblive/blob/master/buster/config/package-lists/system.list.chroot#L30 - adding the cryptsetup packages to my package-lists

And that's about it.

Any ideas as to why I'm getting this error? Thanks!

-SG