Oracle HCM Cloud invoke: You do not have permission to access business object [Workers]

Summary:

We are trying to retrieve updated assignment data using the Employee Assignment Atom Feed and have a requirement to retrieve the full assignment record. From reading the documentation, it seems like we may need to retrieve the full business object. However, the checkbox is grayed out:

I tried to alternatively query the REST API by selecting Query, Create, Update or Delete Information when configuring the invoke, but I can't see anything past MajorsLOV:

I was able to query the /hcmRestApi/resources/11.13.18.05/workers API via Postman, so our service user has access to the Workers object from what I can tell.