Exporting jails fails with AbsolutePath error

[gronke]

#  ioc export my-jail /tmp/my-jail.tar.gz
[-] ResourceBackup@my-jail: ...
  [+] ExportConfig@my-jail: OK [0.0s]
  [-] ExportFstab@my-jail: ...
Traceback (most recent call last):
  File "/usr/local/bin/ioc", line 10, in <module>
    sys.dd:exit(cli())
  File "/usr/local/lib/python3.6/site-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python3.6/site-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python3.6/site-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python3.6/site-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/ioc_cli/export.py", line 102, in cli
    backup_format=_format
  File "/usr/local/lib/python3.6/site-packages/ioc_cli/__init__.py", line 91, in print_events
    for event in generator:
  File "/usr/local/lib/python3.6/site-packages/libioc/ResourceBackup.py", line 487, in export
    yield from self._export_fstab(event_scope=_scope)
  File "/usr/local/lib/python3.6/site-packages/libioc/ResourceBackup.py", line 566, in _export_fstab
    "backup:///"
  File "/usr/local/lib/python3.6/site-packages/libioc/Config/Jail/File/Fstab.py", line 533, in replace_path
    replacement
  File "/usr/local/lib/python3.6/site-packages/libioc/Config/Jail/File/Fstab.py", line 96, in __setitem__
    dict.__setitem__(self, key, libioc.Types.AbsolutePath(value))
  File "/usr/local/lib/python3.6/site-packages/libioc/Types.py", line 63, in __init__
    f"Expected AbsolutePath to begin with /, but got: {sequence}"
ValueError: Expected AbsolutePath to begin with /, but got: backup:////root/.iocage-pkg