WFM API 400 Error on Bulk Schedule Upload for Premium App

Just noticed that the /api/v2/wfm/schedules/upload endpoint is rejecting our batch requests with a 400 Bad Request, citing invalid date formats despite the payload strictly adhering to the ISO 8601 standard documented for the platform API.

Our integration handles multi-org scheduling synchronization, and this regression started after the last patch cycle. The error response does not specify which record is failing, making it difficult to isolate the issue within the 500-row batch. We are using the standard JWT authentication flow for the primary org, and the same payload works correctly in the sandbox environment. Is there a stricter validation rule now enforced in production for the start/end time fields, or is this a known issue with the bulk upload handler?

It depends, but typically the WFM API is stricter than the general platform APIs regarding timezone offsets in ISO 8601 strings.

"startDateTime": "2023-10-27T09:00:00+00:00"

Ensure every record explicitly includes the +00:00 suffix rather than relying on default UTC assumptions.