A system administrator has created a UI Policy to make several fields mandatory on the incident form when the 'Category' field equals 'Software'. The policy works correctly when creating a new incident: if the user selects 'Software', the fields become mandatory. However, when viewing an existing incident and changing the category to 'Software', the fields do not become mandatory. The administrator verifies that the condition is correctly set to 'Category equals Software' and the action sets mandatory true on the target fields. The UI Policy is active and the order is not relevant. What is the most likely reason for this behavior?