Workstations are not being removed from database

Hi there

We are running ZCM 11.2 on SLES 11 with a MS SQL database.
I have done some testing and then I delete a workstation either via ZCC or from the server command prompt zman wd /Devices/Workstations/Testmachine.
It tells me the workstation has been deleted.

Looking at the workstation, the machine remains in a managed start and after a agent refresh re-appears in the database.

I have tried this a number of times and confirmed the machine has been deleted and then it re-appears.

Is this working as designed or what is the process here to delete workstation from the back end.

Thanks
Mark