Passphrase not recognized on encrypted bootable Kali-USB

Hello,

TL;DR
An encrypted and persistent bootable Kali-pendrive works fine when I boot it from the PC were I made it.
But when I boot the USB from another PC the encryption-passphrase is not recognized.
What is going wrong?

The long story:
I made a persistent and encrypted bootable Kali-USB following the tutorial: "Adding USB Persistence with LUKS Encryption"
https://docs.kali.org/downloading/ka...sb-persistence
I used GParted for making the partitions, (step 2 in the tutorial),
but from step 3 and further I used the terminal and followed the tutorial strictly (initializing the LUKS encryption, set up the persistence.conf, etc)

When I boot the USB everything works fine. I did a full upgrade of all packages and after a reboot all upgrades are still there.
Also I made a new file (just a text-file) and after a reboot the new file is still there. So persistant works.
During boot I was of course asked for the passphrase. And this works also.

But when I try to boot the USB from another PC the passphrase is not recognized. And yes, I am 100 % sure I did not make a typo and I did not have CAPS-LOCK on.
When I try to boot the USB from my laptop, the USB is not recognized in the BIOS. But maybe this is another problem.

So,
On PC-1 everything works fine.
On PC 2 the passphrase is not recognized.
On Laptop the USB is not recognized in BIOS.

What is wrong here? What did I wrong? How can I boot the Kali-USB from whatever desktop/laptop?

I don' t know if it is important, but PC-1 is an AMD-64bit, PC-2 is an Intel-64b, and laptop is a Thinkpad X220 (Intel 64b)
I used the official ISO from https://kali.org/downloads, latest version 2018.1, default desktop (Gnome), checked and verified sha256sum

I appreciate all your help, and if you need more information, please let me know.

Many thanks in advance,


Xuddie