[Exim] Exim not responding w/o Strace

I've been noticing a strange happening here and I'm wondering if anyone
has any ideas about it.

I'm running Exim 3.33 on a RedHat 8.0Beta machine, and on a RedHat 7.3
machine. Each has exim listening on a non-standard smtp port (4000,
because my ISP decided to block the smtp port if it's not to their
server) and it seems that exim will just sit there doing nothing unless
it's being actively straced.

I can send mail to the port 4000 and the connection request is
answerred, but it just sits there for litterally 4-5+ minutes after
connect, no welcome logo or anything.

I have exim running at nice level -20 as a test, same result. Now as
soon as I strace it (strace -p `pidof exim`) it IMMEDIATELY wakes up and
handles the mail perfectly. Then if I close Strace and send more mail
it's back to no responce again.

Anyone ever experienced this? Is there a fix?

I am going to D/:L and test exim 4.0 on the RH 8.0Beta box and see if it
works any better. If it does I'll let you know.

-- Dan