To make sure I understand, if a user is logged onto the machine, the sdclient_taskxxx.log does not get created at all?
Also was the distribution package originally created in an older version, or have you recreated it in version 9.6?
No, it doesn't. It happens because when an user is logged onto the machine, the task doesn't run in it.
I did both situation but no success.
If the sdclient_task logs are not being created at all then we will need to look at policysync and see if the device is successfully receiving the policy. You can find the policysync.log and policysync.exe.log in the programdata\landesk\log directory on the client.
Does the policy xml get downloaded to the programdata\landesk\policies folder?
This one will probably be tricky to investigate. I would suggest contacting support and opening a case.