[Exim] parsing problem in exim 3.953?

I can't quite explain this problem:
getafix:/etc/mail# exim -bt root@localhost
root@localhost cannot be resolved at this time:
failed to expand "/var/local/mailman/lists/${lc" for require_files: "${lc" is not a known operator (or a } is missing in a variable reference)

It comes from this, which was copied straight from exim 3.

list_director:
driver = accept
require_files = MAILMAN_HOME/lists/${lc:$local_part}/config.pck
retry_use_local_part
transport = list_transport

If I just have
require_files = MAILMAN_HOME/lists/$local_part/config.pck

Full debugging shows:
local_part=root domain=localhost
checking require_files
---0 Get 135088632    96       expand.c 1673
---0 Get 135088728    80       string.c  349
---0 Rst 135088632    **       expand.c 3001 24576
---0 Get 135088632   144       string.c  349
list_director router deferred: file check
root@localhost cannot be resolved at this time:
  failed to expand "/var/local/mailman/lists/${lc" for require_files: "${lc" is not a known operator (or a } is missing in a variable reference)
search_tidyup called

Is this a bug or is this my fault?

Thanks,
Marc
--
Microsoft is to operating systems & security ....
                                      .... what McDonalds is to gourmet cooking

Home page: http://marc.merlins.org/ | Finger marc_f@??? for PGP key