bzr crashed with KeyError in annotate()

Binary package hint: bzr

The file had local changes. I could not reproduce when I tried to annotate the same file again.

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: bzr 2.3.1-1ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-7.39-generic 2.6.38
Uname: Linux 2.6.38-7-generic x86_64
Architecture: amd64
BzrDebugFlags: set()
BzrVersion: 2.3.1
CommandLine: ['/usr/bin/bzr', 'explorer']
CrashDb: bzr
Date: Sun Apr 3 15:16:49 2011
ExecutablePath: /usr/bin/bzr
FileSystemEncoding: UTF-8
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha amd64 (20110212)
InterpreterPath: /usr/bin/python2.7
Locale: en_NZ.UTF-8
Platform: Linux-2.6.38-7-generic-x86_64-with-Ubuntu-11.04-natty
ProcCmdline: /usr/bin/python /usr/bin/bzr explorer
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, no user)
 LANG=en_NZ.UTF-8
 LANGUAGE=en_NZ:en
PythonVersion: 2.7.1
SourcePackage: bzr
Title: bzr crashed with KeyError in annotate(): u'current:/home/username/Projects/unity/unity'
UpgradeStatus: No upgrade log present (probably fresh install)
UserEncoding: UTF-8
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/qbzr/lib/trace.py", line 321, in reports_exception_decorate
    return f(*args, **kargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/qbzr/lib/annotate.py", line 399, in initial_load
    self.annotate(self.annotate_tree, self.fileId, self.path)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/qbzr/lib/annotate.py", line 493, in annotate
    rev = gv.revid_rev[revid]
KeyError: u'current:/home/username/Projects/unity/unity'