WFM Schedule API 400 Bad Request via Terraform Provider

Ran into a weird issue today with genesyscloud_wfm_schedule resource. TF 1.9.4, Provider 1.36.0, Region ap-southeast-2.

Applying schedule changes returns 400. API docs state:

“The start_time and end_time must be within the defined work week boundaries.”

My JSON is valid. Timestamps are correct for Sydney TZ. Error payload is empty. Is this a known provider issue with WFM schedule validation?