Just for fun, since I still had it installed and haven't gotten around to cleaning up the remote data, I updated to latest (v0.14.1) and tried the restore tasks again.
Both the single file restore and the folder restore worked, though the single file restore still didn't have any progress indicator I could see.
Looking through the changelog, nothing really stood out to me as something which would have fixed this. Not really sure what went wrong the first time around, perhaps it was network issues with Hetzner?