App Composer FCL values not showing in FFS Work Skill Conditions (Service Work Order)

Summary:

I am looking for some guidance regarding a limitation we are hitting with field sync between Service Work order and Fusion field service.
Fixed choice list type custom fields of work order are available to select on work skill condition in FFS however we don't see values to select hence it's blocking us from using these fields

Question: Has anyone successfully used a Service Work Order App Composer FCL (_c) for Work Skill Conditions in FFS?

Content (please ensure you mask any confidential information):

The Setup:
We have created custom Fixed Choice List (FCL) fields (e.g., Language_c