Data Action deployment failing with 400 on payload validation

Configuration is broken for some reason…

Provider v1.15.4. US-1 Prod.
Applying genesyscloud_data_action fails. HTTP 400.

Error:

Error: POST /api/v2/analytics/data-actions: 400 Bad Request
{"errors":[{"code":"invalid.parameter","message":"Payload validation failed for field: parameters.type"}]}

HCL snippet:

parameters {
 name = "orderId"
 type = "string"
}

Docs say this is valid. Terraform plan succeeds. Apply fails. Any ideas?