[Exim] rejected mail sometimes losing the original (2.12)

I realise that I'm not up with the latest but hopefully somebody may
have some ideas....

I have noticed recently that sometimes when exim has rejected a mail
item, the returned mail has nothing after the
"...This is a copy of the message, including..." line. The log file
shows no error just the smaller amount of data, the error does not
repeat, nothing in any log files etc.

The machine which did this (we have a pair of main hubs) is lightly
loaded with plenty of spare resources.

We've been running 2.12 for a while and exim since 1.73 on these
machines for sometime (late 1997) with nothing like this occurring
before (no recent OS changes etc).

Thanks

-- 
Alan Thew                                       alan.thew@???
Computing Services,University of Liverpool      Fax: +44 151 794-4442