Samba don't delete pid files if shut down zentyal server

[zentyalhk]

hello

all three pid files (nmbd.pid, samba.pid, smbd.pid) in folder /opt/samba4/var/run are not be deleted when server was shut down (restart) via web interface.
Hence samba start fail next server startup.

syslog:
...
Feb 23 01:09:53 ki-host smbd[3473]: [2013/02/23 01:09:53.305085,  0] ../source3/smbd/server.c:1280(main)
Feb 23 01:09:53 ki-host smbd[3473]:   standard input is not a socket, assuming -D option
Feb 23 01:09:53 ki-host smbd[3473]: [2013/02/23 01:09:53.306513,  0] ../lib/util/pidfile.c:110(pidfile_create)
Feb 23 01:09:53 ki-host smbd[3473]:   ERROR: smbd is already running. File /opt/samba4/var/run/smbd.pid exists and process id 927 is running.
Feb 23 01:09:53 ki-host kernel: [   74.041264] init: samba4 main process (3442) terminated with status 1
...

These lines are repeated many times.

Only manual deletion pid files brings samba up to normal operation.

How can I change this?

If shut down with 'init 6' from ssh console samba starts up with no error.   

regards