POST /api/v2/architect/flows/{flowId}/versions/{versionId}/scripting returns HTTP 500 Internal Server Error. The payload contains a simple Set Custom Attribute action targeting a string field. Validated the JSON structure against the OpenAPI spec multiple times. Using JMeter 5.6 with 10 concurrent threads against US1 environment. The issue occurs only when the attribute name includes special characters like underscores or hyphens. Standard alphanumeric names work fine. Checked the response headers and there is no helpful error message in the body, just a generic server error. Tried reducing concurrency to 1 thread but the error persists for those specific attribute names. This is blocking our load test suite validation for agent scripting workflows. Need to understand if there is a known limitation with special characters in attribute names during API updates or if this is a backend bug. Any insights on how to debug this further or work around it?