KeyError while running verify

[Pastafarianist]

WebDAV GET /path/to/backup.vol579.difftar.gpg request with headers: {'Connection': 'keep-alive', 'Authorization': 'Basic <long-string-here>'}
WebDAV data length: 4
WebDAV response status 200 with reason 'OK'.
Deleting /tmp/duplicity-7CltV8-tempdir/mktemp-M2iDvp-592
Processed volume 585 of 4543
Traceback (most recent call last):
  File "/usr/bin/duplicity", line 1530, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1524, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1378, in main
    do_backup(action)
  File "/usr/bin/duplicity", line 1457, in do_backup
    verify(col_stats)
  File "/usr/bin/duplicity", line 860, in verify
    for backup_ropath, current_path in collated:
  File "/usr/lib/python2.7/dist-packages/duplicity/diffdir.py", line 276, in collate2iters
    relem1 = riter1.next()
  File "/usr/lib/python2.7/dist-packages/duplicity/patchdir.py", line 516, in integrate_patch_iters
    for patch_seq in collated:
  File "/usr/lib/python2.7/dist-packages/duplicity/patchdir.py", line 388, in yield_tuples
    setrorps(overflow, elems)
  File "/usr/lib/python2.7/dist-packages/duplicity/patchdir.py", line 377, in setrorps
    elems[i] = iter_list[i].next()
  File "/usr/lib/python2.7/dist-packages/duplicity/patchdir.py", line 127, in difftar2path_iter
    multivol_fileobj.close() # aborting in middle of multivol
  File "/usr/lib/python2.7/dist-packages/duplicity/patchdir.py", line 248, in close
    if not self.addtobuffer():
  File "/usr/lib/python2.7/dist-packages/duplicity/patchdir.py", line 236, in addtobuffer
    self.tarinfo_list[0] = self.tar_iter.next()
  File "/usr/lib/python2.7/dist-packages/duplicity/patchdir.py", line 343, in next
    self.set_tarfile()
  File "/usr/lib/python2.7/dist-packages/duplicity/patchdir.py", line 332, in set_tarfile
    self.current_fp = self.fileobj_iter.next()
  File "/usr/bin/duplicity", line 759, in get_fileobj_iter
    backup_set.volume_name_dict[vol_num],
KeyError: 580

duplicity 0.7.03
Python 2.7.9
Debian Jessie
Target filesystem: WebDAV