Stuck on a validation error when attempting to bulk upload schedules for external users via the Workforce Management API. The integration is designed to sync shift data from a third-party ERP into Genesys Cloud for a multi-tenant AppFoundry deployment. When posting to the /api/v2/wfm/schedules/bulk endpoint, the system consistently returns a 400 Bad Request with the message Invalid schedule data: User ID does not belong to an active organization. The payload includes valid external user IDs that are correctly linked to the primary organization through the partner hierarchy. The OAuth token used for the request possesses the wfm:admin scope and is refreshed via the standard PKCE flow without issue. Internal users process correctly, but the external accounts fail during the validation phase. The JSON structure matches the schema provided in the developer documentation, including correct time zone offsets and shift boundaries. We have verified that the external users are active and have valid skill assignments. Is there a known limitation regarding bulk schedule operations for external users in the current API version, or is additional configuration required in the organization settings to permit this operation?