I doubt that LISTSERV itself is doing this. The closest I can come to
this (with Eudora) is:
Subject: [TEST] IMPRESOS PROYECTOS I+D DE INVESTIGACI=D3N B=C1SICA NO
ORIENTADA
DEL PLAN NACIONAL IDT 2000-2003 DISPONIBLES EN INTERNET ,
and if I have IETFHDR set instead of SUBJECTHDR (no attempt made by LISTSERV
to prettyprint the headers) I get
Subject: IMPRESOS PROYECTOS I+D DE INVESTIGACI=D3N B=C1SICA NO ORIENTADA DEL
PLAN NACIONAL IDT 2000-2003 DISPONIBLES EN INTERNET ,
I suspect that the problem is in either or both the receiving or sending mail
client(s). I will make the point that this subject line is extremely long
and some attempt should probably be made to shorten it anyway.
Nathan