[exim] rerouted-to

Hello,

I am running exim 4.69 on OpenBSD 4.2.

I have some strange behavior on one of my servers
2008-02-11 16:20:09 [5930] 1JOaS0-0001Xe-7J <= correction@wallex
H=(relay.intra.mrw.wallonie.be) [193.190.18.193]:58327
I=[157.164.172.68]:25 P=esmtps X=TLSv1:AES256
-SHA:256 CV=no S=1795
id=26194423.01202743200636.JavaMail.apache@SRVLAMP5V T="Sauvegarde de la
correction (8758-7890-2731)" from <correction@wallex> for gerard_felte
n@???

The mail from correction@wallex seems to be accepted for delivery,
although it should not as it is unqualified. Obviously, the mail is
rejected at yahoo.

I have "qualify_domain = wallonie.be" in my configuration file, but the
behavior stays the same whether I put it or not.

193.190.18.193 is in my relay_from_hosts

After running exim -bhc 193.190.18.193 with the same data as formerly, I saw

>>> re-routed to correction@???

wallex.wallonie.be has an A record and has no smtp server, so my
sender_verify/defer_ok doesn't reject this mail as it should.

As the mail is sent via SMTP and not locally submitted and
sender_unqualified_hosts is not defined anywhere, I don't see any reason
why exim tries to qualify the unqualified domain name. So what could
cause the "re-routing" of this mail?

Could someone enlighten me?

Thanks