crash on "bzr add" -- changed symlink to actual directory

I removed a symlink and instead created an actual directory with the same name. "bzr add" crashed with the following output. After using "bzr --keep remove DIR_NAME" and then "bzr add DIR_NAME" everything worked just fine.

$ bzr add
bzr: ERROR: exceptions.AttributeError: children

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 857, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 797, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 499, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.5/site-packages/bzrlib/builtins.py", line 387, in run
    no_recurse, action=action, save=not dry_run)
  File "/usr/lib/python2.5/site-packages/bzrlib/mutabletree.py", line 52, in tree_write_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/mutabletree.py", line 432, in smart_add
    elif subf in this_ie.children:
AttributeError: children

bzr 1.6.1 on python 2.5.2 (linux2)
arguments: ['/usr/bin/bzr', 'add']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_US.UTF-8'
plugins:
  bzrtools /usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools [1.6.0]
  launchpad /usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad [unknown]
*** Bazaar has encountered an internal error.
    Please report a bug at https://bugs.launchpad.net/bzr/+filebug
    including this traceback, and a description of what you
    were doing when the error occurred.