WFM Quality Assessment API 500 Error on Nested Rubric Update via Terraform

Why does this setting trigger a 500 Internal Server Error when deployed via Terraform?

Environment: US-1 Production. Provider v1.15.4.

Attempting to update genesyscloud_quality_assessment resource. The apply fails consistently when modifying the rubric block with nested items. Simple updates to name or description succeed.

Error log from Terraform apply:

Error: PUT https://api.us-gov-1.genesyscloud.com/api/v2/quality/assessments/12345: 500 Internal Server Error
Response body: {"message":"An internal server error occurred","errors":[{"code":"internal.server.error","message":"Failed to parse rubric structure"}]}

The HCL structure matches the schema definition. Validated JSON against the API spec manually. The issue appears specific to the items array depth.

Resource snippet:

resource "genesyscloud_quality_assessment" "qa_rubric" {
 name = "Call Quality Check"
 enabled = true
 
 rubric {
 name = "Standard Rubric"
 items {
 name = "Greeting"
 type = "choice"
 # nested config fails here
 }
 }
}

Manual API call via Postman with same payload returns 200. Terraform provider seems to serialize the nested objects incorrectly or the API endpoint has a bug with bulk updates.

Is this a known issue with the quality management module in v1.15.4? Looking for a workaround or if a specific attribute needs to be flattened before passing to the provider.