QM Scorecard evaluation webhook throwing 400 on custom attributes

Problem

Express middleware is hammering v2/analytics/quality/scorecard-evaluations. GC version sits at 2024-5.612.0. Endpoint throws a 400 immediately. Custom attribute array is definitely populated, it’s right there in the console. Inspector doesn’t flag anything. Logs are quiet. Request finishes in 150ms.

{
 "code": "invalidArgument",
 "message": "Property 'customAttributes[0].value' is required but missing"
}