samba - Jun 2014 - CentOS6.5 Samba 3.6.9 Windows8.1 login possible after 15 minutes after logoff

Hello,
in school We have CentOS6.5 server with Samba3.6.9 (default from 
CentOS3.6.9 repository).
Clients are WinXP, Win7 and Win8.1, We use roaming profiles.

Everything is working perfect, except that when user logs off from 
Win8.1 client, he is not able to log in for about 15 minutes to any 
Win8.1 client at school. After 15 minutes it is possible again.
I do have pretty standard smb.conf, no special tweaks, Samba is PDC, 
extra attributes on etx4 active, inherit acls enabled on home shares:

*******************************************************
[global]
     workgroup = ORANGEFACTORY
     server string = Linux
     netbios name = BIGORANGE
     hosts allow = 127.0.0.1 192.168.1.0/24
     log level = 1
     log file = /var/log/samba/log.%m
     max log size = 100

     security = user
     passdb backend = tdbsam
     domain master = yes
     domain logons = yes
     logon script = scripts\%G\logon.bat
     logon drive = o:

     add user script = /usr/sbin/useradd "%u" -g users
     add group script = /usr/sbin/groupadd "%g"
     add machine script = /usr/sbin/useradd -n -c "Workstation (%u)"
-M
-d /nohome -s /bin/false "%u"
     delete user script = /usr/sbin/userdel "%u"
     delete user from group script = /usr/sbin/userdel "%u"
"%g"
     delete group script = /usr/sbin/groupdel "%g"

     local master = yes
     os level = 128
     preferred master = yes
     dns proxy = No

     csc policy = disable
     socket options = SO_KEEPALIVE

     map archive = no
     map hidden = no
     map read only = no
     map system = no
     username map = /etc/samba/smbusers
     store dos attributes = yes
     hide files = 
/profile/profile.V2/profile.V3/profile.V4/bin/desktop.ini/$Recycle.bin/
     map to guest = Bad User

[homes]
     comment = Domaci slozka
     browseable = yes
     writeable = yes
     valid users = %S, %D%w%S
     inherit acls = Yes

**************************************************************

I have found that probably the oplock of NTUser.DAT is a problem. Below 
is a samba log of the machine, user has just logged off from.

[2014/06/25 10:09:49.432186,  3] smbd/process.c:1662(process_smb)
   Transaction 38400 of length 120 (0 toread)
[2014/06/25 10:09:49.432273,  3] smbd/process.c:1467(switch_message)
   switch message SMBtrans2 (pid 9685) conn 0x7f802ccbf110
[2014/06/25 10:09:49.432355,  3] 
smbd/trans2.c:8044(call_trans2setfilepathinfo)
   call_trans2setfilepathinfo(8) profile.V4/ntuser.ini (fnum 14628) 
info_level=1004 totdata=40
[2014/06/25 10:09:49.432415,  3] smbd/trans2.c:7621(smbd_do_setfilepathinfo)
   smbd_do_setfilepathinfo: profile.V4/ntuser.ini (fnum 14628) 
info_level=1004 totdata=40
[2014/06/25 10:09:49.432952,  3] smbd/process.c:1662(process_smb)
   Transaction 38401 of length 45 (0 toread)
[2014/06/25 10:09:49.433032,  3] smbd/process.c:1467(switch_message)
   switch message SMBclose (pid 9685) conn 0x7f802ccbf110
[2014/06/25 10:09:49.433090,  3] smbd/reply.c:4848(reply_close)
   close fd=-1 fnum=14628 (numopen=2)
[2014/06/25 10:09:49.433181,  2] smbd/close.c:696(close_normal_file)
   testuser closed file profile.V4/ntuser.ini (numopen=1) NT_STATUS_OK
[2014/06/25 10:09:49.436388,  3] smbd/process.c:1662(process_smb)
   Transaction 38402 of length 134 (0 toread)
[2014/06/25 10:09:49.436466,  3] smbd/process.c:1467(switch_message)
   switch message SMBntcreateX (pid 9685) conn 0x7f802ccbf110
[2014/06/25 10:09:49.436593,  3] smbd/vfs.c:905(check_reduced_name)
   check_reduced_name [profile.V4/NTUSER.DAT] [/home/students/2009/testuser]
[2014/06/25 10:09:49.436669,  3] smbd/vfs.c:1039(check_reduced_name)
   check_reduced_name: profile.V4/NTUSER.DAT reduced to 
/home/students/2009/testuser/profile.V4/NTUSER.DAT
[2014/06/25 10:09:49.436735,  3] smbd/dosmode.c:159(unix_mode)
   unix_mode(profile.V4/NTUSER.DAT) returning 0644
[2014/06/25 10:09:49.436834,  2] smbd/open.c:746(open_file)
   testuser opened file profile.V4/NTUSER.DAT read=Yes write=Yes (numopen=2)
[2014/06/25 10:09:49.436904,  3] 
smbd/oplock_linux.c:142(linux_set_kernel_oplock)
   linux_set_kernel_oplock: got kernel oplock on file 
profile.V4/NTUSER.DAT, file_id = 902:2780559:0 gen_id = 1881283690
[2014/06/25 10:09:49.437570,  3] smbd/process.c:1662(process_smb)
   Transaction 38403 of length 76 (0 toread)
[2014/06/25 10:09:49.437651,  3] smbd/process.c:1467(switch_message)
   switch message SMBtrans2 (pid 9685) conn 0x7f802ccbf110
[2014/06/25 10:09:49.437711,  3] 
smbd/trans2.c:5026(call_trans2qfilepathinfo)
   call_trans2qfilepathinfo: TRANSACT2_QFILEINFO: level = 1006
[2014/06/25 10:09:49.437779,  3] 
smbd/trans2.c:5255(call_trans2qfilepathinfo)
   call_trans2qfilepathinfo profile.V4/NTUSER.DAT (fnum = 14629) 
level=1006 call=7 total_data=0
[2014/06/25 10:09:49.438733,  3] smbd/process.c:1662(process_smb)
   Transaction 38404 of length 120 (0 toread)
[2014/06/25 10:09:49.438813,  3] smbd/process.c:1467(switch_message)
   switch message SMBtrans2 (pid 9685) conn 0x7f802ccbf110
[2014/06/25 10:09:49.438877,  3] 
smbd/trans2.c:8044(call_trans2setfilepathinfo)
   call_trans2setfilepathinfo(8) profile.V4/NTUSER.DAT (fnum 14629) 
info_level=1004 totdata=40
[2014/06/25 10:09:49.438934,  3] smbd/trans2.c:7621(smbd_do_setfilepathinfo)
   smbd_do_setfilepathinfo: profile.V4/NTUSER.DAT (fnum 14629) 
info_level=1004 totdata=40
[2014/06/25 10:10:10.064876,  3] smbd/oplock.c:271(initial_break_processing)
   initial_break_processing: called for 902:2780559:0/1881283690
   Current oplocks_open (exclusive = 2, levelII = 0)
[2014/06/25 10:10:40.089350,  0] smbd/oplock.c:330(oplock_timeout_handler)
   Oplock break failed for file profile.V4/NTUSER.DAT -- replying anyway

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