dovecot-antispam plugin not work

[basti]

Hello,
I try to use the plugin for my dovecot in debian.
It seem that the /usr/bin/sa-learn-pipe.sh is not execute.
When I run /usr/bin/sa-learn-pipe.sh from commandline logfiles are created.
I also read https://johannes.sipsolutions.net/files/antispam.html

In syslog you can see fist move a mail from "z_SPAM" to INBOX and then
move a mail from INBOX to "z_SPAM".

Can you please help?
Best regards

Config and log's are append.

dpkg -l | grep dovecot
ii  dovecot-antispam                  2.0+20130912-2               
amd64        Dovecot plugins for training spam filters
ii  dovecot-core                      1:2.2.13-12~deb8u1           
amd64        secure POP3/IMAP server - core files
ii  dovecot-imapd                     1:2.2.13-12~deb8u1           
amd64        secure POP3/IMAP server - IMAP daemon
ii  dovecot-pgsql                     1:2.2.13-12~deb8u1           
amd64        secure POP3/IMAP server - PostgreSQL support

### log
root at vsrv78105:/etc/dovecot# /etc/init.d/dovecot restart
[ ok ] Restarting dovecot (via systemctl): dovecot.service.
root at vsrv78105:/etc/dovecot# tail -f /var/log/syslog | grep imap
Nov  3 20:02:45 vsrv78105 dovecot: imap-login: Warning: Killed with
signal 15 (by pid=1 uid=0 code=kill)
Nov  3 20:02:48 vsrv78105 dovecot: master: Dovecot v2.2.13 starting up
for imap (core dumps disabled)
Nov  3 20:03:03 vsrv78105 dovecot: imap-login: Login: user=<xxx>,
method=PLAIN, rip=xxx, lip=xxx, mpid=14954, TLS, session=<pqb/NGpAvgBP8o1u>
Nov  3 20:03:03 vsrv78105 imap: antispam: plugin initialising (2.0-notgit)
Nov  3 20:03:03 vsrv78105 imap: antispam: verbose debug enabled
Nov  3 20:03:03 vsrv78105 imap: antispam: "Spam" is exact match spam folder
Nov  3 20:03:03 vsrv78105 imap: antispam: "SPAM" is exact match spam folder
Nov  3 20:03:03 vsrv78105 imap: antispam: "z_SPAM" is exact match spam
folder
Nov  3 20:03:03 vsrv78105 imap: antispam: no unsure folders
Nov  3 20:03:03 vsrv78105 imap: antispam: "Trash" is exact match trash
folder
Nov  3 20:03:03 vsrv78105 imap: antispam: "trash" is exact match trash
folder
Nov  3 20:03:03 vsrv78105 imap: antispam: pipe backend tmpdir /tmp
Nov  3 20:03:13 vsrv78105 imap: antispam: mailbox_is_unsure(INBOX): 0
Nov  3 20:03:13 vsrv78105 imap: antispam: mailbox_is_trash(z_SPAM): 0
Nov  3 20:03:13 vsrv78105 imap: antispam: mailbox_is_trash(INBOX): 0
Nov  3 20:03:13 vsrv78105 imap: antispam: mail copy: from trash: 0, to
trash: 0
Nov  3 20:03:13 vsrv78105 imap: antispam: mailbox_is_spam(z_SPAM): 0
Nov  3 20:03:13 vsrv78105 imap: antispam: mailbox_is_spam(INBOX): 0
Nov  3 20:03:13 vsrv78105 imap: antispam: mailbox_is_unsure(z_SPAM): 0
Nov  3 20:03:13 vsrv78105 imap: antispam: mail copy: src spam: 0, dst
spam: 0, src unsure: 0
Nov  3 20:03:14 vsrv78105 dovecot: imap-login: Login: user=<xxx>,
method=PLAIN, rip=xxx, lip=xxx, mpid=14959, TLS, session=<KxqnNWpAvwBP8o1u>
Nov  3 20:03:14 vsrv78105 imap: antispam: plugin initialising (2.0-notgit)
Nov  3 20:03:14 vsrv78105 imap: antispam: verbose debug enabled
Nov  3 20:03:14 vsrv78105 imap: antispam: "Spam" is exact match spam folder
Nov  3 20:03:14 vsrv78105 imap: antispam: "SPAM" is exact match spam folder
Nov  3 20:03:14 vsrv78105 imap: antispam: "z_SPAM" is exact match spam
folder
Nov  3 20:03:14 vsrv78105 imap: antispam: no unsure folders
Nov  3 20:03:14 vsrv78105 imap: antispam: "Trash" is exact match trash
folder
Nov  3 20:03:14 vsrv78105 imap: antispam: "trash" is exact match trash
folder
Nov  3 20:03:14 vsrv78105 imap: antispam: pipe backend tmpdir /tmp
Nov  3 20:04:05 vsrv78105 imap: antispam: mailbox_is_unsure(z_SPAM): 0
Nov  3 20:04:05 vsrv78105 imap: antispam: mailbox_is_trash(INBOX): 0
Nov  3 20:04:05 vsrv78105 imap: antispam: mailbox_is_trash(z_SPAM): 0
Nov  3 20:04:05 vsrv78105 imap: antispam: mail copy: from trash: 0, to
trash: 0
Nov  3 20:04:05 vsrv78105 imap: antispam: mailbox_is_spam(INBOX): 0
Nov  3 20:04:05 vsrv78105 imap: antispam: mailbox_is_spam(z_SPAM): 0
Nov  3 20:04:05 vsrv78105 imap: antispam: mailbox_is_unsure(INBOX): 0
Nov  3 20:04:05 vsrv78105 imap: antispam: mail copy: src spam: 0, dst
spam: 0, src unsure: 0
^C

root at vsrv78105:/etc/dovecot# ls -la /tmp/
insgesamt 8864
drwxrwxrwt  8 root     root       12288 Nov  3 20:07 .
drwxr-xr-x 22 root     root        4096 Jun 17 14:41 ..
drwxrwxrwt  2 root     root        4096 Nov  1 14:16 .font-unix
drwxrwxrwt  2 root     root        4096 Nov  1 14:16 .ICE-unix
drwxrwxrwt  2 root     root        4096 Nov  1 14:16 .Test-unix
drwxrwxrwt  2 root     root        4096 Nov  1 14:16 .X11-unix
drwxrwxrwt  2 root     root        4096 Nov  1 14:16 .XIM-unix

root at vsrv78105:/etc/dovecot# ls -la /etc/dovecot/sa-learn-pipe.sh
-rwxr-xr-x 1 root root 769 Nov  3 19:38 /etc/dovecot/sa-learn-pipe.sh

#########################

config

###
90-plugin.conf

plugin {
  #setting_name = value

  antispam_backend = pipe
  antispam_debug_target = syslog
  antispam_verbose_debug = 1
# antispam_mail_sendmail_args= --username=%u       
  antispam_mail_spam_arg  = --spam
  antispam_mail_notspam_arg  = --ham
  antispam_mail_program = /etc/dovecot/sa-learn-pipe.sh
  antispam_spam = Spam;SPAM;z_SPAM                  
  antispam_trash = Trash;trash                      
}

###

sa-learn-pipe.sh

#!/bin/bash
set -x
pid=$$
# remove the # from next line to background learner
#(
{
echo "$(date) ${pid}-start ($*) /tmp/sendmail-msg-$$.txt"
set -x
#id -a
#env

cat > /tmp/sendmail-msg-${pid}.txt
/usr/bin/sa-learn "$@" /tmp/sendmail-msg-${pid}.txt
echo "$(date) $$-end rc=$?"
} >/tmp/antispam.${pid}.log 2>&1

echo "cat antispam.${pid}.log"
cat /tmp/antispam.${pid}.log >>/tmp/sa-learn-pipe.log
rm -f /tmp/antispam.${pid}.log /tmp/sendmail-msg-${pid}.txt
true
# remove the # from next line to background learner
#) &
exit 0