How to migrate between repositories?

To alleviate my problems with one repo – two SFTP accounts [1] I’ve decided to migrate one of the hosts to a new repo on the same NAS. I’m temporarily giving up on deduplication until I’ll setup a Kopia server.

So I’ve just created a repo:

kopia repository create sftp --username=r --host=v --path=/mnt/backup/r --keyfile ~/.ssh/id_ed25519_backup --known-hosts ~/.ssh/known_hosts.kopia 
<new password>

Then I’ve forgot that I didn’t copy the old repo config, but I manage to reconnect to the old repo and have two configuration files.

Yet when I try to do a migration:

kopia snapshot migrate --apply-ignore-rules --source-config=repository_l.config --all
Enter password to open repository: 

ERROR failed to open repository: invalid repository password
ERROR can't open source repository: can't open source repository: invalid repository password

Wait, what? I’m using the password to the old repo, to connect to the old repo, as I am connected to the new repo.

But when I input the new repo password:

❯ kopia snapshot migrate --apply-ignore-rules --source-config=repository_l.config --all
Enter password to open repository: 

 * 0 hashing, 0 hashed (0 B), 0 cached (0 B), uploaded 0 B, estimating...
Migration finished.

What am I getting wrong about the procedure?

[1] One repo, two SFTP accounts, repo is locked to a given client at a time - #6 by iBackup