Failure on restore 0.12.3 to 0.13+dev (docker)

I tried to restore nightly backup from gogs/gogs:0.12.3 to fresh installation of gogs/gogs:0.13+dev

su git -c ‘./gogs restore --from=“gogs-backup-20210509094909.zip”’

I’m getting the following error report:

[FATAL] […io/gogs/internal/cmd/restore.go:122 runRestore()] Failed to import ‘custom’: rename tmp/gogs-backup/custom /data/gogs: invalid cross-device link

Environment: QNAP NAS with container station (docker).

Any ideas? Greetings
Haiko