[lxd] lxc copy --refresh to remote error: can't rename because file exists

I’ve used this command on my backup server to make the initial backup and it works.

/snap/bin/lxc copy T620:vaultwarden bkp-vaultwarden --refresh -s machines

when I rerun the command to really refresh the backup I get the following error.

Error: Failed instance creation: Error transferring instance data: Failed creating instance on target: rename /var/snap/lxd/common/lxd/storage-pools/machines/containers/migration.2682469171/snap0/snap0 /var/snap/lxd/common/lxd/storage-pools/machines/containers-snapshots/bkp-vaultwarden/snap0: file exists

snap0 exists because it should exist so I don’t understand why the refresh fails.

Both servers are running lxd 5.11

Any ideas @monstermunchkin ? Could this be related to optimized refresh?