Hi user16748,
Are you using the devkit or custom board for AGX Orin?
Have you also verified with the latest R35.5.0?
[ 12.723289] ERROR: encrypted dev /dev/nvme0n1p2 is not LUKS device.
It seems something wrong in your NVMe partition.
Could you share the full steps how you flash the external NVMe with disk-encryption enabled?