Openhabian SD mirror not booting

I have been testing SD card mirroring using the openhabian-config menu. I have had some success but am having trouble replicating results. I have no problem mirroring the main SD card to a card in an external card reader. I’ve been searching through the forum and have found what seem like people having a similar problem. If I was to make a guess I’d say the problem is with the PARTUUID but where to from there.

I’m running openhabian 3 on a pi4 4gb. in my fault finding I’ve connected the pi (normally headless) to my TV to see where the boot is hanging. I have attached a photo of what’s displayed. Apologies for not being able to copy and past directly to this post.

Below is a rundown of my testing.

I’ve tried with mirroring to 3 different SD cards. All boot the first time I mirror to them but after additional mirrors are SD syncs they fail to boot. On my last attempt I mirrored to an SD card then tested that mirror. It booted perfectly. I then returned to booting off the ‘master’ SD card and returned the mirrored SD card, that had just booted, to the external reader. According to the sdr*.timer files the next sync was due to take place at 2am. I made a change to my site map to then prove the auto sync but the next morning when I tested the mirrored card it wouldn’t boot.

I’ve also tried the dd function on my mac to clone the SD card. This worked but is hanging at the same point during boot.

I’ve tried multiple variations on the above description. It seems that once a card doesn’t boot it won’t boot again even if re-mirrored. When I mirror to a new card I use the openhabian-config menu to disable mirroring before then setting it up again for the new card.

I’ve had a similar experience with enabling backup from within openhabian.conf file during initial setup. It worked on initial setup, I then tested the backup, it booted as expected. I then performed another initial setup of openhabian (for unrelated issue) using the same cards but now the backup didn’t work - it would boot.

What am I missing? is this related to PARTUUID? How would I fix this?