Please reflash the board 2 w/o disk-encryption and get the result to check if the board 1 and board 2 are the same.
So, they are not relating to your reboot issue.
It seems caused from the following message.
[ 4.929935] trusty-log panic notifier - trusty version Built: 08:57:16 Feb 19 2022
You didn’t add -i ./XXX.key in Step2 to generate the encrypted image for external device.
Please check if the following thread could help for your case.
Why the initrd_flash can encrypt the disk without SBKPKC mode - #20 by lhoang