What is the reason this setting causes the Contact List API to return a 400 Bad Request when injecting ServiceNow ticket IDs via the Dynamic List endpoint? The payload structure matches the schema, yet the validation fails specifically on the custom attribute mapping.
The environment runs Genesys Cloud EU-West-1 with a nightly Data Action sync to ServiceNow. The webhook payload confirms the ticket ID exists, but the outbound campaign fails to ingest the contact during the synchronization window. Error message indicates a mismatch in the custom_attributes type definition.