Using Code List Restrictions you have set the Default value for field Ticket Type to be empty, but this field still defaults to 'Employee Support Ticket'.
Reproducing the Issue
Go to Service work center.
Go to Tickets view.
Click on New.
The Type field is filled with 'Employee Support Ticket' as per Code List Restrictions.
Navigate to Administrator work center.
Go to General settings view and open Code List Restrictions.
Here the rule set is for Business Object = Ticket , Control Field = Any and Code to Restrict = Ticket Type.
Go to Default Values tab and set the Code Default value to Empty , which means for any control field the default value of Ticket Type should be empty.
This is not working as the Ticket Type field is filled with 'Employee Support Ticket'.
As per current system behavior we cannot have Ticket Type field as Blank.
For any instance of the Ticket, we need to know the Ticket type, because there are lot of follow on features like Status Management,ATP , Release to ERP and all these functionalities are dependent on the Ticket type.
Also, this has to be decided when the instance is created and cannot be changed later, so we need a value for Ticket Type field.
We suggest you to maintain one of the Ticket Type values as Default value.
Ticket, default,control field , KBA , employee support , ticket type , LOD-CRM-SRP , Service Request Processing , LOD-CRM-PM-SRV , C4C Product Management - Service , Problem