PhotoLab 5 v5.1.1 crash after CCC backup

I am running PL5 on a MacPro/Monterey. I have an external Thunderbolt harddisk with a Carbon Copy Cloner backup of the boot volume.

PL5 crashes if I try to start it after CCC performs a backup. If I unmount and re-mount the backup harddisk, PL5 starts up and runs fine.