HCM workers REST API 'Batched' Payload to change employee name records

Summary:

We are looking to use the 'workers' REST API to remove trailing spaces from employee name records using batching.
Despite having the 'effective-Of' Header set to RangeMode=CORRECTION, the payload fails with a 400 Bad Request: Effective-Of header is required for UPDATE operation on date effective resource.

Content (please ensure you mask any confidential information):

Has anyone successfully used batch payloads to update HCM date-effective records?

If so, could you please provide guidance on whether this is possible, and if so, how to get this working?

I have tried all sorts of variations on the effective-Of Header attribute to no avail.