[EXIM] Empty MAIL FROM

I've just noticed that when Exim is sending a delivery error report it uses
a blank envelope from address (MAIL FROM:<>). Is this intentional?

Some mail hosts are rejecting them because of this (sprintmail.com MX hosts
for example).

Thanks,

Mike
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Mike Zanker                | Email: A.M.Zanker@???
ACS Network Services Group | Tel  : +44 1908 652726
The Open University        | Fax  : +44 1908 652193
Milton Keynes, UK          | PGP public key available

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