overchan in 2.3

[N]

Hi,

Two days ago I changed over to the external overchan.  This afternoon I
found several articles that were posted elsewhere last night, were stored
in the history database here and retrievable by Message-ID, but their
overview information had been overwritten by another article in the same
group.

~news/etc/newsfeeds has

overview!\
        :*\
        :Tc,WntO:/usr/local/news/bin/overchan

I believe this is the correct syntax (save for the path a direct
cut-n-paste from a post Russ Allbery recently made on news.software.nntp
about this), useoverchan is set to true in inn.conf (this isn't documented
in inn.conf(5) is it?).  Am I missing something, did anyone else notice
anything similar, can I do anything to help finding the cause? (articles,
tokens, config etc. available on request naturally.)

Unfortunately innd can't really keep up with a full feed and serve readers 
when it also has to write out the overview information so disabling the
external overchan is something I'd like to avoid...

Thanks for any help,


	-- Niels.