There is a serious bug in CP release  5 (all SLUs <= 504) which causes CP to
check only the first four characters of the userid on a match for a class D CP
CHANGE command.  That is, if you  do a CP CHANGE  LIST R ALL CLASS  Z, all the
files in LISTSERV's reader  will be changed, as well as  the files on LISTTEST
and LISTING  and... This happens only  if the 4-characters userid  does exist,
which was the case  at CEARN (it is our test list). If  you have a list called
MAIL-L or  MAILBOOK, then all  files in the  MAILER reader would  be affected,
etc. This  is a very  dangerous bug indeed.  This also explains  why rejection
notices got  unexpectedly distributed to a  list which had nothing  to do with
it.
 
  Sure enough, IBM did  a CLC USERID,SFBUSER which I have  always said is very
bad programming practice. USERID being defined as  DS 2F, it has a length of 4
and not 8.  To fix this you  must hit module DMKCSW. This  is another argument
for moving to OCO:  with OCO you have strictly no means  to solve the problem.
Your system  therefore gets seriously damaged,  whereupon you can sue  IBM and
get them  to give  you some free  program products to  compensate for  loss of
spool files :-)
 
  Eric