Reporting API 400 Error during Zendesk Analytics Migration

Dealing with a very strange bug here with the Reporting API while trying to replicate our Zendesk ticket volume dashboards. The POST to /api/v2/analytics/conversations/details/query fails immediately.

{ "errors": [ { "code": "bad_request", "message": "Invalid metric configuration" } ] }

The metric conversation.count works fine in Zendesk, but Genesys rejects the equivalent conversation.total_count in this specific query structure. Is there a syntax change for the migration mapping?