ValueError: Something wrong with: cp_off = 2314752, cp_size = 3 source_size = 494614, size = 89493

Bazaar version : 2.4.1
OS Version : Ubuntu 10.04 and 11.04
Python version : 2.6 and 2.7

When I try to branch this branch : lp:unifield-server, I have this traceback :

bzr: ERROR: exceptions.ValueError: Something wrong with: cp_off = 2314752, cp_size = 3 source_size = 494614, size = 89493

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 946, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 1150, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 699, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 721, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/builtins.py", line 1307, in run
    source_branch=br_from)
  File "/usr/lib/python2.7/dist-packages/bzrlib/bzrdir.py", line 453, in sprout
    create_tree_if_local=create_tree_if_local)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 131, in run
    self.cleanups, self.func, self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/bzrdir.py", line 494, in _sprout
    result_repo.fetch(source_repository, fetch_spec=fetch_spec)
  File "/usr/lib/python2.7/dist-packages/bzrlib/repository.py", line 724, in fetch
    find_ghosts=find_ghosts, fetch_spec=fetch_spec)
  File "/usr/lib/python2.7/dist-packages/bzrlib/decorators.py", line 217, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/vf_repository.py", line 2499, in fetch
    find_ghosts=find_ghosts)
  File "/usr/lib/python2.7/dist-packages/bzrlib/fetch.py", line 75, in __init__
    self.__fetch()
  File "/usr/lib/python2.7/dist-packages/bzrlib/fetch.py", line 102, in __fetch
    self._fetch_everything_for_search(search_result)
  File "/usr/lib/python2.7/dist-packages/bzrlib/fetch.py", line 130, in _fetch_everything_for_search
    stream, from_format, [])
  File "/usr/lib/python2.7/dist-packages/bzrlib/vf_repository.py", line 1962, in insert_stream
    src_format, is_resume)
  File "/usr/lib/python2.7/dist-packages/bzrlib/vf_repository.py", line 2026, in insert_stream_without_locking
    self.target_repo.texts.insert_record_stream(substream)
  File "/usr/lib/python2.7/dist-packages/bzrlib/groupcompress.py", line 1661, in insert_record_stream
    for _ in self._insert_record_stream(stream, random_id=False):
  File "/usr/lib/python2.7/dist-packages/bzrlib/groupcompress.py", line 1802, in _insert_record_stream
    bytes = record.get_bytes_as('fulltext')
  File "/usr/lib/python2.7/dist-packages/bzrlib/groupcompress.py", line 474, in get_bytes_as
    self._bytes = block.extract(self.key, self._start, self._end)
  File "/usr/lib/python2.7/dist-packages/bzrlib/groupcompress.py", line 280, in extract
    bytes = apply_delta_to_source(self._content, content_start, end)
  File "_groupcompress_pyx.pyx", line 546, in bzrlib._groupcompress_pyx.apply_delta_to_source (bzrlib/_groupcompress_pyx.c:4861)
  File "_groupcompress_pyx.pyx", line 497, in bzrlib._groupcompress_pyx._apply_delta (bzrlib/_groupcompress_pyx.c:4385)
ValueError: Something wrong with: cp_off = 2314752, cp_size = 3 source_size = 494614, size = 89493

But, if I launch:
bzr branch lp:unifield-server -r 3363
cd unifield-server
bzr pull

It's ok.