Genesyscloud_report 400 Bad Request - Invalid JSON Payload via Terraform

Stumbled on a weird bug today with genesyscloud_report resource. Pushing HCL returns 400 Bad Request with Invalid report payload. JSON matches OpenAPI spec.

Context:
Terraform v1.9.8
Provider v1.65.0
Region: ap-southeast-2 (Sydney)

the error is generic. no details in terraform logs. curling the api directly works fine with same json.

snippet:

resource "genesyscloud_report" "agent_summary" {
 name = "agent_summary_report"
 description = "Agent summary"
 type = "agent-summary"
 filters {
 ... 
 }
}

apply fails immediately.

Error: failed to create report: 400 Bad Request

on main.tf line 10, in resource "genesyscloud_report" "agent_summary":
10: resource "genesyscloud_report" "agent_summary" { 

has anyone seen this with report resources? seems like provider validation is too strict or broken.

thanks.