Incus-migrate rsync error, exit status 23

Hello,
I’m currently trying to figure out a way to migrate my unprivileged LXC containers (not LXD) to Incus. On LXC I’m using the loop backend due to its simplicity - I know this backend hasn’t got the best reputation on dev side, but it’s working great for my usage.
Attempts with lxc-to-incus failed without an error message - copying seemed to be fine without any error but when finished the container couldn’t be started because the new volume is missing (gets deleted somehow after finishing the migration without any notice?)
Now I’m trying the “bare metal migration” with bin.linux.incus-migrate.x86_64. This fails because of a rsync error.

./bin.linux.incus-migrate.x86_64 --rsync-args "--exclude tmp/"
Please provide Incus server URL: 10.0.100.152
Certificate fingerprint: e4a37ef7c0af34bffa3e331bf4553d1d828852e2e2256ffe0badd02d43857b5f
ok (y/n)? y

1) Use a certificate token
2) Use an existing TLS authentication certificate
3) Generate a temporary TLS authentication certificate
Please pick an authentication mechanism above: 3

Your temporary certificate is:
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

A temporary client certificate was generated, use `incus config trust add` on the target server.

Press ENTER after the certificate was added to the remote server: 

Remote server:
  Hostname: host01
  Version: 6.8

Would you like to create a container (1) or virtual-machine (2)?: 1
Name of the new instance: test
Please provide the path to a root filesystem: /
Do you want to add additional filesystem mounts? [default=no]: 

Instance to be created:
  Name: test
  Project: default
  Type: container
  Source: /

Additional overrides can be applied at this stage:
1) Begin the migration with the above configuration
2) Override profile list
3) Set additional configuration options
4) Change instance storage pool or volume size
5) Change instance network

Please pick one of the options above [default=1]: 
IO error encountered -- skipping file deletion
Transferring instance: test: 566.09MB (11.75MB/s)Error: Failed sending filesystem volume: Failed to rsync: exit status 23
rsync: [sender] opendir "/tmp/incus-migrate_mount_3936632469/rootfs/lost+found" failed: Permission denied (13)
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1338) [sender=3.2.7]

Any ideas why it doesn’t even work when skipping /tmp?
Thank you!

Found a way to actually do it… Is a bit odd, but works. Could maybe help somebody:

copy rootdev to target machine (with scp, …)
mount rootdev to folder (e.g. rootfs/)
compile lxc-remap (GitHub - unmanarc/lxc-remap: Remap UID/GID cloning LXC containers with new subuid/subgid ranges.)
execute lxc-remap: lxc-remap <original start g/uid> <original end g/uid> 0 65536 rootfs/
execute incus-migrate and follow instructions