macOS 15.3 has been released. It includes a fix for the replicator failure in 15.2.
Once installed, SuperDuper “Erase, then copy" backups should start working again.
Thanks for your patience!
EDIT: I think I goofed, and this is the 15.3 RC, and LOOKED like a public release. Apologies for the inadvertent disclosure...it wasn't marked as such in the update notice.
I held off updating to 15.3; do I need to do an erase-then-copy after updating, or will my scheduled smart updates continue to be bootable as per normal?
@kraigschmidt As indicated in "What's going to happen?”, the various instructions, etc, a Smart Update *preserves* but does not *copy* the OS in Big Sur and later.
It can't. Only the replicator can copy macOS.
So, to copy (or update) the OS (as opposed to the data volume), you must use Erase, then copy. Smart Update can then be used to update everything else.