Bug 468

Do you know why the script is not working when sudo another user within the shell script, which has a loop? I tried below two examples, both didn't work. My user1 doesn't need password for sudo to user2, we have already set up that. The sudo works when there's no loop. But example-3 woks well.
Example1:-
=================
#!/usr/bin/ksh
echo "Script started" > $LOG_FILE
for i in `ls nyt_sartre_*.gpg`
do
   sudo su - user2 << EOF
   mv -f $pgpfn $actual_fn  
   rc=$?
   EOF
done
echo "Script completed" >> $LOG_FILE

Example2:-
=================
#!/usr/bin/ksh
echo "Script started" > $LOG_FILE
for i in `ls nyt_sartre_*.gpg`
do
   sudo su - user2 << EOF
   mv -f $pgpfn $actual_fn  
   rc=$?
   EOF
done
echo "Script completed" >> $LOG_FILE

Example3:-
=================
# This works well
#!/usr/bin/ksh
echo "Script started" > $LOG_FILE
   sudo su - user2 << EOF
   mv -f abc.txt $home/backup/  
   rc=$?
   EOF
echo "Script completed" >> $LOG_FILE