400 Bad Request on genesyscloud_flow set_user_data block

Trying to push a new IVR flow structure to prod using the CX-as-Code provider. The apply hangs on the genesyscloud_flow resource for about two minutes before dumping a 400 Bad Request. Provider is locked to v1.73.0 against a US-East org. Terraform v1.9.0. The issue centers on the set_user_data block within the flow definition. Config looks solid based on the latest schema docs, but the API rejects the value field when referencing a dynamic query parameter. Error message mentions Invalid block attribute 'value'. State file shows the flow exists, so it’s not a creation problem. It’s an update rejection. Logs from the run are doing jack all. No payload validation detail. Console shows the flow version is stuck in a partial publish state. Commenting out the block lets the apply finish instantly. Putting it back kills the run again. Provider might be serializing the reference wrong. Missing a wrapper object in the JSON output maybe. Also tried using genesyscloud_flow_version directly but same result. Tried invalidating the cache. Tried forcing refresh. Nothing changes. The flow works fine in the UI when built manually. Just the provider chokes on the syntax. Maybe the schema definition in the provider is outdated compared to the API. The error response body is empty. Just the status code. Network trace shows the PUT request to /api/v2/flows/{id} returning 400. The payload includes the flow definition JSON. The set_user_data block is nested under blocks. The value object has type set to reference. The data object has source and key. This matches the example in the provider docs exactly. Yet the API throws the error. State drift backup is clean. No manual changes detected. Here is the resource block causing the crash.

resource "genesyscloud_flow" "ivr_main" {
 name = "Main IVR - Prod"
 description = "Customer tier routing"
 enabled = true

 definition {
 blocks {
 set_user_data {
 name = "set_tier"
 value {
 type = "reference"
 data {
 source = "queryparam"
 key = "tier"
 }
 }
 }
 }
 }
}