Jira Service Management (JSM) projects handle custom fields differently than Jira Software projects.
This documentation provides a detailed view of which field dependencies are supported in JSM projects, based on the current technical limitations and product behavior.
Prerequisites for enabling dependencies in a JSM project
A manual action is required for the initial setup and whenever you need to configure Jira field dependencies for a new portal or a new request type.
In “Settings” tab, click on the Synchronize button to be up-to-date.
Supported dependencies for Custom Fields used on JSM projects