PATCH call transfer to queue returns 409 Conflict

Trying to transfer an active voice interaction to a different queue via the Conversations API. I’m using the PATCH endpoint on /api/v2/interactions/{interactionId}. The docs say I need to update the to property with the new queue ID.

Here is the payload I’m sending:

{
 "from": {
 "id": "current-queue-id",
 "type": "queue"
 },
 "to": {
 "id": "target-queue-id",
 "type": "queue"
 }
}

The request fails with a 409 Conflict. The error message says "message": "Conflicting update for interaction". I’ve checked the ETag headers. I’m including the current ETag in the If-Match header. The interaction state is ACTIVE.

I tried fetching the latest interaction data right before the PATCH to get a fresh ETag. Still getting the 409. The script is just using a REST Proxy to hit this endpoint. Is there a specific sequence required for queue transfers? Or maybe the from field shouldn’t be included in the PATCH body?

Any ideas on what’s causing the conflict?