Bulk Export 400 on WebRTC Recording Metadata

Having some issues getting my configuration to work… trying to export WebRTC session recordings to our S3 bucket in EU-West-1 BYOC. The POST to /api/v2/bulkexports/exportjobs fails immediately.

The error payload is:

{
 "errors": [
 {
 "code": "invalid_filter",
 "message": "Invalid filter: recording_url is not a valid property for digital channels."
 }
 ]
}

I need this for a legal discovery request. We have a strict chain of custody requirement. The interactions are tagged correctly in the platform, and I can see the media URLs in the UI. However, the bulk export API seems to treat WebRTC differently than standard digital channels like chat or email.

Is there a specific filter syntax for softphone/WebRTC recordings? Or does this endpoint simply not support media attachment extraction for this channel type? I have tried using media_attachment_url as well but get the same 400 Bad Request.

Environment: Genesys Cloud BYOC EU-West-1
Endpoint: POST /api/v2/bulkexports/exportjobs
Filter attempted: recording_url and media_attachment_url

This is blocking a retention policy audit. Any guidance on how to retrieve these specific recordings via API would be appreciated. The standard download links expire too quickly for our legal hold process.