Queued mail not retrying

[nxds]

We had a problem for a short period yesterday when spamd was struggling under load and exim failed to deliver with a 'transport filter timeout'. However, it appear that exim did not attempt any retries until several hours later. Can anyone shed light on this?

Here's a log entry:

2007-05-16 10:42:32 1HoFzj-0001eI-IO spam acl condition: error reading from spamd socket: Connection timed out
2007-05-16 10:42:32 1HoFzj-0001eI-IO <= xxxxx@xxx.ac.uk H=(relay1.xxxxx.ac.uk) [129.xx.xxx.165] P=esmtp S=6104 id=002201c7979b$cb48cf20$6c7601a3@xxxxx.ac.uk T="Booking enquiry"
2007-05-16 10:42:32 cwd=/var/spool/exim 3 args: /usr/sbin/exim -Mc 1HoFzj-0001eI-IO
2007-05-16 10:47:33 1HoFzj-0001eI-IO <sales@lxxxx.com>: virtual_sa_userdelivery transport output: An error was detected while processing a file of BSMTP input.
2007-05-16 10:47:33 1HoFzj-0001eI-IO == sales@lxxxxxx.com R=virtual_sa_user T=virtual_sa_userdelivery defer (0): transport filter timeout while writing to pipe
2007-05-16 19:50:43 1HoFzj-0001eI-IO => sales <sales@lxxxxx.com> R=virtual_sa_user T=virtual_sa_userdelivery
2007-05-16 19:50:43 1HoFzj-0001eI-IO Completed

The message was received at 10.47 but not retried until 19.50! WTF?

[gegervision]

I'm having the exact same issue.