I installed 2021-10-30-raspios-bullseye-arm64-lite on my SSD. The booted, ran through some common options with raspi-config, like localization. Rebooted, as requested.
Then I did a sudo apt update, and a sudo apt upgrade. Rebooted. I didn't do much then, but had to shut it down, for other reasons, so did a sudo shutdown -h now.
Later I wanted to reboot, but got in an endless loop. I know very little about Linux, so here's the text on boot, where it loops:
Starting helper to synchronize boot up for ifupdown...
Finished helper to synchronize boot up for ifupdown.
Checking in progress on 1 disk(counting from 0 to 100%)
Then the system rboots, and gets stuck in the same place.
So I tried downloading 2021-10-30-raspios-bullseye-arm64-lite again, although it runs great on a SD-card. But first I tried creating a FAT32 partition on Windows, checked the disk with Hard Disk Sentinel (84% health and no errors), ran a dos chkdsk, then, ran a trim via O&O Defrag. I then booted on the RPI, did 2 reboots, and 2 shutdowns. No issues.
Then did the usual stuff with first boot in raspi-config on the RPI, and finished with sudo apt update, and a sudo apt upgrade. Then rebooted.
I then tried 2 additional reboots, with no issues. Then I did a sudo shutdown -h now. Unplugged the supply, and the error returns.
So the error lies within the apt upgrade, and with a following full shutdown.