In Helsinki, users who had the knowledge_manager role (for example, the Owner of a Knowledge Base) were able to create or edit KB categories.
In Istanbul, this does not happen anymore: in some cases the Categories related list on the KB form shows the "NEW" button, and sometimes it doesn't, but even if it does, clicking it causes a "Action not authorized" error to be displayed.
The delete operation is never allowed, this is expected behaviour. Unwanted KB categories may only be disabled by setting the Active flag to false.
Steps to Reproduce
Login as administrator.
Assign Joe Employee as the owner of a KB.
Verify that Joe automatically was given the knowledge_manager role.
Login as Joe Employee.
Open his given KB article, notice that the Categories related list does not display the NEW button, or, if it does, it's not functional.
This problem is fixed in the Jakarta release. In case an upgrade is not possible yet, please open an incident with SN support, to check if a workaround can be applied.
Related Problem: PRB715609