POST /api/v2/flows/executions returns 422 on valid integer input

Configuration is broken for some reason… I’m hitting POST /api/v2/flows/executions to trigger a flow from an external service. The request returns 422 Unprocessable Entity.

{
 "flowId": "abc-123-def-456",
 "inputs": {
 "customer_id": "CUST_99",
 "priority": 5
 }
}

Response indicates inputs.priority is invalid, but the flow definition expects an integer.

The schema validation in the Data Action output seems correct. Why is the API rejecting the type?